HDU 2819 swap（二分图匹配并记录路径)

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <vector>
#define LL long long
using namespace std;
const int MAXN = 100 + 10;
int G[MAXN][MAXN];
int vis[MAXN];
int match[MAXN];
int N;
int path(int u)
{
for(int v=1;v<=N;v++)
{
if(G[u][v] && !vis[v])
{
vis[v] = 1;
if(match[v] == -1 || path(match[v]))
{
match[v] = u;
return 1;
}
}
}
return 0;
}
int MaxMatch()
{
int res = 0;
memset(match, -1, sizeof(match));
for(int u=1;u<=N;u++)
{
memset(vis, 0, sizeof(vis));
res += path(u);
}
return res;
}
int a[MAXN], b[MAXN];
int main()
{
while(scanf("%d", &N)!=EOF)
{
memset(G, 0, sizeof(G));
for(int i=1;i<=N;i++)
{
for(int j=1;j<=N;j++)
scanf("%d", &G[i][j]);
}
int ans = MaxMatch();
if(ans < N)
{
printf("-1\n");
continue;
}
int acc = 0;
for(int i=1;i<=N;i++)
{
int j;
for(j=1;j<=N;j++)
if(match[j] == i)
break;
if(j != i)
{
a[++acc] = i;
b[acc] = j;
swap(match[i], match[j]);
}
}
printf("%d\n", acc);
for(int i=1;i<=acc;i++)
{
printf("C %d %d\n", a[i], b[i]);
}
}
return 0;
}