{ }codelper
iterating listsappendingsimulationP0180

A tournament where winning tires you

n players line up in bracket order and play a tournament. The first line gives n, and each of the next n lines gives one player's "name strength" in bracket order. In each round the remaining players are paired from the front, two at a time (1st with 2nd, 3rd with 4th, …), and each pair plays a match. If an odd number of players remain, the last player advances to the next round without a match, with strength unchanged. In a match the stronger player wins; with equal strength, the player standing earlier in the pair wins. The winner gets tired and loses strength equal to the quotient of (loser's strength ÷ 2). The loser is eliminated, and the next round's line is the winners (and the player who advanced without a match) in the same order as this round. Rounds repeat until one player remains. After each round, print the remaining players in order as "name:strength" on one line, separated by single spaces. On the last line print the remaining player as "champion name". If n is 1 there are no rounds, so print only the one line "champion name".

Input
1 ≤ n ≤ 1000, 1 ≤ strength ≤ 1,000,000,000 (integers).
Names are 1 to 10 lowercase English letters and all different
Output
One line per round (the remaining players as "name:strength"), and "champion name" on the last line
Example 1 · stdin
5
ari 50
bo 70
cy 40
dan 40
eve 90
stdout
bo:45 cy:20 eve:90
bo:35 eve:90
eve:73
champion eve
Example 2 · stdin
2
x 9
y 9
stdout
x:5
champion x
main.py
Input (stdin)

When you run, these lines are fed to input()/stdin in order (the program doesn't stop to ask).

$ Ready

Open this on a computer to write and run code. On mobile you can read the problem and the solutions.

In other languagesShow solutions by language · 8 languages

This simulation walks the current line two cells at a time, appends each winner to a new list, and swaps in the new list at the end of the round.
Stepping by two: Python range(0, len(p), 2), JS/TS/Java/C#/C/C++ i += 2, Craykon for (i = 0; i < n; i = i + 2) (Korean 반복).
Appending: Python append, JS/TS push, Java/C# add/Add, C++ push_back, Craykon Add (Korean 넣기).
C writes each winner to cell k at the front of the same array, needing no second array (k ≤ i, so it never overwrites a cell not yet read).
Trap one: shortening the end to only visit full pairs, as in range(0, len(p) - 1, 2), silently drops the last player when the count is odd.
Trap two: "the quotient of ÷ 2" is exactly / between ints in Java, C#, C and C++, but JS/TS / keeps the fraction and gives values like 45.5.
Use Math.floor(x / 2); Python uses // and Craykon Mathf.Quot(x, 2) (Korean 수학.몫; Craykon / also gives a fraction).
Strength is positive, so truncating and flooring agree.
Trap three: on equal strength the earlier player wins, so pick the earlier player with >=; writing > lets the later player win.
Strength is at most 10^9 and only goes down, so int is plenty.

Pythonmain.py · 23 lines
import sys lines = sys.stdin.read().split("\n")n = int(lines[0])players = []for line in lines[1:1 + n]:    name, power = line.split()    players.append((name, int(power))) out = []while len(players) > 1:    nxt = []    for i in range(0, len(players), 2):        if i + 1 == len(players):          # 짝이 없는 마지막 선수는 그대로 올라간다            nxt.append(players[i])            continue        a, b = players[i], players[i + 1]        win, lose = (a, b) if a[1] >= b[1] else (b, a)   # 같으면 앞 선수        nxt.append((win[0], win[1] - lose[1] // 2))    players = nxt    out.append(" ".join(f"{name}:{power}" for name, power in players))out.append(f"champion {players[0][0]}")print("\n".join(out))
JavaScriptmain.js · 24 lines
const lines = require("fs").readFileSync(0, "utf8").split("\n");const n = Number(lines[0]);let players = lines.slice(1, 1 + n).map((line) => {  const [name, power] = line.trim().split(" ");  return { name, power: Number(power) };}); const out = [];while (players.length > 1) {  const next = [];  for (let i = 0; i < players.length; i += 2) {    if (i + 1 === players.length) {      next.push(players[i]); // 짝이 없는 마지막 선수는 그대로 올라간다      continue;    }    const [a, b] = [players[i], players[i + 1]];    const [win, lose] = a.power >= b.power ? [a, b] : [b, a]; // 같으면 앞 선수    next.push({ name: win.name, power: win.power - Math.floor(lose.power / 2) }); // /는 소수가 나온다  }  players = next;  out.push(players.map((p) => `${p.name}:${p.power}`).join(" "));}out.push(`champion ${players[0].name}`);console.log(out.join("\n"));
TypeScriptmain.ts · 32 lines
import { readFileSync } from "node:fs"; interface Player {  name: string;  power: number;} const lines: string[] = readFileSync(0, "utf8").split("\n");const n = Number(lines[0]);let players: Player[] = lines.slice(1, 1 + n).map((line) => {  const [name, power] = line.trim().split(" ");  return { name, power: Number(power) };}); const out: string[] = [];while (players.length > 1) {  const next: Player[] = [];  for (let i = 0; i < players.length; i += 2) {    if (i + 1 === players.length) {      next.push(players[i]); // 짝이 없는 마지막 선수는 그대로 올라간다      continue;    }    const a = players[i];    const b = players[i + 1];    const [win, lose] = a.power >= b.power ? [a, b] : [b, a]; // 같으면 앞 선수    next.push({ name: win.name, power: win.power - Math.floor(lose.power / 2) }); // /는 소수가 나온다  }  players = next;  out.push(players.map((p) => `${p.name}:${p.power}`).join(" "));}out.push(`champion ${players[0].name}`);console.log(out.join("\n"));
JavaMain.java · 41 lines
import java.io.*;import java.util.*; public class Main {    public static void main(String[] args) throws IOException {        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));        int n = Integer.parseInt(br.readLine().trim());        List<String> names = new ArrayList<>();        List<Integer> power = new ArrayList<>();        for (int i = 0; i < n; i++) {            String[] p = br.readLine().trim().split(" ");            names.add(p[0]);            power.add(Integer.parseInt(p[1]));        }         StringBuilder out = new StringBuilder();        while (names.size() > 1) {            List<String> nextNames = new ArrayList<>();            List<Integer> nextPower = new ArrayList<>();            for (int i = 0; i < names.size(); i += 2) {                if (i + 1 == names.size()) { // 짝이 없는 마지막 선수는 그대로 올라간다                    nextNames.add(names.get(i));                    nextPower.add(power.get(i));                    continue;                }                int a = power.get(i), b = power.get(i + 1);                int win = a >= b ? i : i + 1; // 같으면 앞 선수                int lose = Math.min(a, b);                nextNames.add(names.get(win));                nextPower.add(Math.max(a, b) - lose / 2); // int끼리 /는 몫            }            names = nextNames;            power = nextPower;            StringJoiner sj = new StringJoiner(" ");            for (int i = 0; i < names.size(); i++) sj.add(names.get(i) + ":" + power.get(i));            out.append(sj).append('\n');        }        out.append("champion ").append(names.get(0)).append('\n');        System.out.print(out);    }}
C#Main.cs · 40 lines
using System;using System.Collections.Generic;using System.Linq;using System.Text; class Program{    static void Main()    {        int n = int.Parse(Console.ReadLine().Trim());        var players = new List<(string Name, int Power)>();        for (int i = 0; i < n; i++)        {            string[] p = Console.ReadLine().Trim().Split(' ');            players.Add((p[0], int.Parse(p[1])));        }         var sb = new StringBuilder();        while (players.Count > 1)        {            var next = new List<(string Name, int Power)>();            for (int i = 0; i < players.Count; i += 2)            {                if (i + 1 == players.Count) // 짝이 없는 마지막 선수는 그대로 올라간다                {                    next.Add(players[i]);                    continue;                }                var (win, lose) = players[i].Power >= players[i + 1].Power // 같으면 앞 선수                    ? (players[i], players[i + 1])                    : (players[i + 1], players[i]);                next.Add((win.Name, win.Power - lose.Power / 2)); // int끼리 /는 몫            }            players = next;            sb.Append(string.Join(" ", players.Select(p => $"{p.Name}:{p.Power}"))).Append('\n');        }        sb.Append($"champion {players[0].Name}\n");        Console.Write(sb);    }}
C++main.cpp · 36 lines
#include <iostream>#include <string>#include <vector> struct Player {    std::string name;    int power;}; int main() {    int n;    std::cin >> n;    std::vector<Player> players(n);    for (auto& p : players) std::cin >> p.name >> p.power;     std::string out;    while (players.size() > 1) {        std::vector<Player> next;        for (size_t i = 0; i < players.size(); i += 2) {            if (i + 1 == players.size()) { // 짝이 없는 마지막 선수는 그대로 올라간다                next.push_back(players[i]);                continue;            }            const Player& a = players[i];            const Player& b = players[i + 1];            const Player& win = a.power >= b.power ? a : b; // 같으면 앞 선수            const Player& lose = a.power >= b.power ? b : a;            next.push_back({win.name, win.power - lose.power / 2}); // int끼리 /는 몫        }        players = next;        for (size_t i = 0; i < players.size(); i++)            out += (i ? " " : "") + players[i].name + ":" + std::to_string(players[i].power);        out += "\n";    }    std::cout << out << "champion " << players[0].name << "\n";}
Cmain.c · 33 lines
#include <stdio.h>#include <string.h> static char name[1000][11];static int power[1000]; int main(void) {    int n;    scanf("%d", &n);    for (int i = 0; i < n; i++) scanf("%10s %d", name[i], &power[i]);     /* 이긴 선수를 같은 배열의 앞쪽에 차례로 당겨 쓴다(k번째 승자는 k번 칸) */    while (n > 1) {        int k = 0;        for (int i = 0; i < n; i += 2, k++) {            int win = i, lose = i + 1;            if (i + 1 == n) { /* 짝이 없는 마지막 선수는 그대로 */                strcpy(name[k], name[i]);                power[k] = power[i];                continue;            }            if (power[i + 1] > power[i]) win = i + 1, lose = i; /* 같으면 앞 선수 */            int p = power[win] - power[lose] / 2;            if (k != win) strcpy(name[k], name[win]); /* 같은 칸끼리 strcpy 하면 겹친 복사라 안 된다 */            power[k] = p;        }        n = k;        for (int i = 0; i < n; i++) printf(i ? " %s:%d" : "%s:%d", name[i], power[i]);        printf("\n");    }    printf("champion %s\n", name[0]);    return 0;}
Craykonmain.cray · 45 lines
n = Console.ReadLine().ToNumber();names = [];power = [];for (i = 0; i < n; i++){    p = Console.ReadLine().Trim().Split();    names.Add(p[0]);    power.Add(p[1].ToNumber());} while (names.Count > 1){    nextNames = [];    nextPower = [];    for (i = 0; i < names.Count; i = i + 2)    {        if (i + 1 == names.Count)        {            // 짝이 없는 마지막 선수는 그대로 올라간다            nextNames.Add(names[i]);            nextPower.Add(power[i]);        }        else        {            win = i;            lose = i + 1;            if (power[i + 1] > power[i])            {                win = i + 1; // 같으면 앞 선수가 이긴다                lose = i;            }            nextNames.Add(names[win]);            nextPower.Add(power[win] - Mathf.Quot(power[lose], 2)); // 7 / 2는 3.5라 몫을 쓴다        }    }    names = nextNames;    power = nextPower;    row = [];    for (i = 0; i < names.Count; i++)    {        row.Add(names[i] + ":" + power[i]);    }    Console.WriteLine(row.Join(" "));}Console.WriteLine("champion " + names[0]);