UVa1609 Foul play

#include <cstdio>
#include <vector>
using namespace std;

const int N = 1024+5;
char table[N][N];

int main()
{
	int n;
	//freopen("in.txt","r",stdin);
	while(scanf("%d",&n) == 1){
		
		vector<int> win,lose;
		for(int i = 1; i <= n; ++i) scanf("%s",table[i]+1);
		for(int i = 2; i <= n; ++i){
			if(table[1][i] == '1') win.push_back(i);
			else lose.push_back(i);
		} 
		
		int num = n;
		while(num > 1){
			vector<int> win2, lose2, final; // phase 3/4
			
			// phase 1: 尽量让黑色和灰色配对
			for(int i = 0; i < lose.size(); ++i){ // 枚举黑色 
				int tolose = lose[i];
				bool matched = false;
				for(int j = 0; j < win.size(); ++j){ // 找一个可以打败他的灰色 
				    int& towin = win[j];
					if(towin > 0 && table[towin][tolose] == '1'){
						printf("%d %d\n",towin,tolose);
						win2.push_back(towin); // 进入下一轮 
						towin = 0; //本轮比赛不能再用了
						matched = true;
						break; 
					}
				}
				if(!matched) final.push_back(tolose);//没有配对的黑色，加入final准备自相残杀 
			}
			// phase 2: 给1号找一个可以打败的对手，剩下的加入final 
			bool first = true;
			for(int i = 0; i < win.size(); ++i){
				int towin = win[i];
				if(towin > 0){
					if(first) { printf("1 %d\n",towin); first = false; }
					else final.push_back(towin);
				}
			}
			// phase 3，4: 黑色任意配对，互相残杀；剩下的任意配对 
			for(int i = 0; i < final.size(); i += 2){
				printf("%d %d\n",final[i],final[i+1]);
				int keep = final[i];
				if(table[final[i+1]][keep] == '1') keep = final[i+1];
				if(table[1][keep] == '1') win2.push_back(keep);
				else lose2.push_back(keep);
			}
			
			win = win2; lose = lose2;
			num/= 2;
		}
	}
	return 0;
 } 

代码是LRJ大佬的，真的强。