HDU2819-Swap-二分图匹配

把矩阵上的1建成边，把边建成点

然后跑一个二分图匹配，就找到了主对角线的元素，之后排个序就可以了

 /*--------------------------------------------------------------------------------------*/

 #include <algorithm>
 #include <iostream>
 #include <cstring>
 #include <ctype.h>
 #include <cstdlib>
 #include <cstdio>
 #include <vector>
 #include <string>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <set>
 #include <map>

 //debug function for a N*M array
 #define debug_map(N,M,G) printf("\n");for(int i=0;i<(N);i++)\
 {for(int j=;j<(M);j++){\
 printf("%d",G[i][j]);}printf("\n");}
 //debug function for int,float,double,etc.
 #define debug_var(X) cout<<#X"="<<X<<endl;
 #define LL long long
 const int INF = 0x3f3f3f3f;
 const LL LLINF = 0x3f3f3f3f3f3f3f3f;
 /*--------------------------------------------------------------------------------------*/
 using namespace std;

 int N,M,T;
 const int maxn = ;
 const int maxm = ;

 struct Edge{
     int to,next;
 }edge[maxm];
 int head[maxn],tot;
 void init()
 {
     tot = ;
     memset(head,-,sizeof head);
 }
 void add_edge(int u,int v)
 {
     edge[tot].to = v;edge[tot].next = head[u];
     head[u] = tot++;
 }

 int linker[maxn];
 bool used[maxn];
 int uN;

 bool dfs(int u)
 {
     for(int i=head[u];~i;i =edge[i].next)
     {
         int v = edge[i].to;
         if(!used[v])
         {
             used[v] = true;
             if(linker[v] == - || dfs(linker[v]))
             {
                 linker[v] = u;
                 return true;
             }
         }
     }
     return false;
 }

 int hungary()
 {
     int res = ;
     memset(linker,-,sizeof linker);
     for(int u=;u<=uN;u++)
     {
         memset(used,false,sizeof used);
         if(dfs(u)) res++;
     }
     return res/;
 }
 vector <pair<int,int> > op;
 int save[maxn];

 bool ok()
 {
     for(int i=;i<=N;i++) if(save[i] != i) return false;
     return true;
 }

 int main()
 {
     while(~scanf("%d",&N))
     {
         uN = *N;
         init();
         for(int i=;i<=N;i++)
         {
             for(int j=,tmp;j<=N;j++)
             {
                 scanf("%d",&tmp);
                 if(tmp == )
                 {
                     add_edge(i,j+N);
                     add_edge(j+N,i);
                 }
             }
         }
         int match = hungary();
         if(match < N)
         {
             printf("-1\n");
         }
         else
         {
             for(int u=;u<=N;u++)
             {
                 int v = linker[u] - N;
                 //printf("[%d,%d]\n",u,v);
                 save[u] = v;
             }
             op.clear();
             while(!ok())
             {
                 for(int i=;i<=N;i++)
                 {
                     if(save[i] != i)
                     {
                         op.push_back(make_pair(i,save[i]));
                         swap(save[i],save[save[i]]);
                     }
                 }
             }
             printf("%d\n",op.size());
             for(int i=;i<op.size();i++)
             {
                 printf("R %d %d\n",op[i].first,op[i].second);
             }
         }
     }
 }