Bit Magic HDU - 4421

  1 // ConsoleApplication2.cpp: 定义控制台应用程序的入口点。
  2 //
  3 
  4 // ConsoleApplication1.cpp: 定义控制台应用程序的入口点。
  5 //
  6 
  7 #include "stdafx.h"
  8 #include<stack>
  9 #include<cstdio>
 10 #include<cstring>
 11 #include<iostream>
 12 #include<algorithm>
 13 #define mem(array) memset(array,0,sizeof(array))
 14 using namespace std;
 15 
 16 const int maxn = 6000;
 17 const int maxm = 999999;
 18 
 19 stack<int> S;
 20 
 21 struct node {
 22     int to, next;
 23 }e[maxm];
 24 
 25 int k, n, tot, index;
 26 int Low[maxn], Dfn[maxn], head[maxn], cmp[maxn],map[505][505];
 27 bool use[maxn];
 28 
 29 void Inite() {
 30     k = tot = index = 0;
 31     mem(Dfn); mem(use); mem(cmp);
 32     memset(head, -1, sizeof(head));
 33 }
 34 
 35 void addedge(int u, int v) {
 36     e[tot].to = v;
 37     e[tot].next = head[u];
 38     head[u] = tot++;
 39 }
 40 
 41 void Tarjan(int u) {
 42     Low[u] = Dfn[u] = ++index;
 43     S.push(u);
 44     use[u] = 1;
 45     for (int i = head[u]; i != -1; i = e[i].next) {
 46         int v = e[i].to;
 47         if (!Dfn[v]) {
 48             Tarjan(v);
 49             Low[u] = min(Low[u], Low[v]);
 50         }
 51         else if (use[v]) {
 52             Low[u] = min(Low[u], Dfn[v]);
 53         }
 54     }
 55     int v;
 56     if (Dfn[u] == Low[u]) {
 57         k++;
 58         do {
 59             v = S.top();
 60             S.pop();
 61             cmp[v] = k;
 62             use[v] = 0;
 63         } while (v != u);
 64     }
 65 }
 66 
 67 bool check() {
 68     for (int i = 0; i < n; i++) {
 69         if (map[i][i]) return false;
 70         for (int j = i + 1; j < n; j++)
 71             if (map[i][j] != map[j][i]) return false;
 72     }
 73     return true;
 74 }
 75 
 76 int main()
 77 {
 78     while (scanf_s("%d", &n) != EOF) {
 79         for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) scanf_s("%d", &map[i][j]);
 80         if (!check()) { puts("NO"); continue; }
 81         bool flag = false;
 82         for (int p = 0; p < 31; p++) {
 83             Inite();
 84             for (int i = 0; i < n; i++) {
 85                 for (int j = i + 1; j < n; j++) {
 86                     if (i % 2 == 1 && j % 2 == 1) {
 87                         if ((map[i][j] >> p) & 1) {
 88                             addedge(i + n, j);
 89                             addedge(j + n, i);
 90                         }
 91                         else {
 92                             addedge(i, i + n);
 93                             addedge(j, j + n);
 94                         }
 95                     }
 96                     else if (i % 2 == 0 && j % 2 == 0) {
 97                         if ((map[i][j] >> p) & 1) {
 98                             addedge(i + n, i);
 99                             addedge(j + n, j);
100                         }
101                         else {
102                             addedge(i, j + n);
103                             addedge(j, i + n);
104                         }
105                     }
106                     else {
107                         if ((map[i][j] >> p) & 1) {
108                             addedge(i, j + n);
109                             addedge(i + n, j);
110                             addedge(j, i + n);
111                             addedge(j + n, i);
112                         }
113                         else {
114                             addedge(i, j);
115                             addedge(j, i);
116                             addedge(i + n, j + n);
117                             addedge(j + n, i + n);
118                         }
119                     }
120                 }    
121             }
122             for (int i = 0; i < 2 * n; i++) if (!Dfn[i]) Tarjan(i);
123             for (int i = 0; i < n; i++) if (cmp[i] == cmp[i + n]) flag = true;
124             if (flag) break;    
125          }
126         if (flag) puts("NO");
127         else puts("YES");
128     }
129     return 0;
130 }