Csu1612:destroy Tunnels

Description

Zuosige always have bad luck. Recently, he is in hospital because of pneumonia. While he was taking his injection, he feels extremely bored. However, clever zuosige comes up with a new game.

Zuosige is playing a computer game called Call of Pneumonia. In the game, Zuosige are pursued by germs which may cause pneumonia. Zuosige is feared, so he wants to destroy the country. The country consists of N cities and for each city, there exits exactly one directed tunnel from it to every.

To destroy bridges, Zuosige gets a magic matrix An*n (ai,j>=0). Then let, if bi,j>0, the bridge from city I to City J would be destroyed.

Now Zuosige wants to know whether he can destroy all tunnels.

Input

The first line contains one integer T, indicating the number of test cases.
In one test case, there is several lines.
In the first line, there is one integer N (1<=n<=1000), indicating the number of cities.
In the following n lines, each line has n integers. These N lines describes matrix A. The j-th integer in i-th line is ai,j.

Output

For each test case, the output "not exists" if any tunnels can be destroyed or "exists" otherwise.

Sample Input

230 1 32 0 11 1 030 1 00 0 00 0 0

Sample Output

Not existsexists

HINT

Source
Test instructions: According to the formula required by the question, can we make the matrix non-0
Because mathematics is not my strong point, in fact, this problem is more guessing.

#include <iostream> #include <stdio.h> #include <string.h> #include <stack> #include <queue& Gt #include <map> #include <set> #include <vector> #include <math.h> #include <bitset> # Include <algorithm> using namespace std; #define LS 2*i #define RS 2*i+1 #define UP (i,x,y) for (i=x;i<=y;i++) #define OFF (i,x,y) for (i=x;i>=y;i--) #define Me M (a,x) memset (A,x,sizeof (a)) #define W (a) while (a) #define LL long Long const double PI = ACOs (-1.0); #define N 1000005 #define MOD 19999997 const int INF = 0X3F3F3F3F;   #define EXP 1e-8 bitset<1005> a[1005];     int main () {int t,n,i,j,k,flag;     cin>>t;         W (t--) {cin>>n;                 Up (I,1,n) {up (j,1,n) {cin>>k;             A[I][J] = (k>0?1:0);         }} (I,1,n) {up (j,1,n) if (A[j][i]) a[j]|=a[i];         } flag = 0; UP (i,1,n) {up (j,1,n) {if (i==j) continue;                     if (!a[i][j]) {flag=1;                 Break         }} if (flag) break;         } if (flag) printf ("exists\n");     else printf ("Not exists\n"); } return 0;  }

Csu1612:destroy Tunnels