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| Time Limit: 1000MS | Memory Limit: 262144KB | 64bit IO Format: %I64d & %I64u |
Description
Valera is a little boy. Yesterday he got a huge Math hometask at school, so Valera didn‘t have enough time to properly learn the English alphabet for his English lesson. Unfortunately, the English teacher decided to have a test on alphabet today. At the test Valera got a square piece of squared paper. The length of the side equals n squares (n is an odd number) and each unit square contains some small letter of the English alphabet.
Valera needs to know if the letters written on the square piece of paper form letter "X". Valera‘s teacher thinks that the letters on the piece of paper form an "X", if:
Help Valera, write the program that completes the described task for him.
Input
The first line contains integer n (3 ≤ n < 300; n is odd). Each of the next n lines contains n small English letters — the description of Valera‘s paper.
Output
Print string "YES", if the letters on the paper form letter "X". Otherwise, print string "NO". Print the strings without quotes.
Sample Input
5
xooox
oxoxo
soxoo
oxoxo
xooox
NO
3
wsw
sws
wsw
YES
3
xpx
pxp
xpe
NO
Source
#include <iostream> using namespace std; int main() { int i,j,n; char c[305][305]; cin>>n; for(i=0;i<n;i++) cin>>c[i]; char tmp1=c[0][0]; char tmp2=c[0][1]; if(tmp1==tmp2) { cout<<"NO"<<endl; return 0; } int flag=1; for(i=0;i<n;i++) {for(j=0;j<n;j++) { if(i==j||i+j==n-1) { if(c[i][j]!=tmp1) { flag=0; break; } } else { if(c[i][j]!=tmp2) { flag=0; break; } }if(!flag) break; } } if(flag) cout<<"YES"<<endl; else cout<<"NO"<<endl; return 0; }
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原文地址：http://www.cnblogs.com/Ritchie/p/5425011.html
