hdu4331 Image Recognition

Image Recognition

Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 964    Accepted Submission(s): 371


Problem DescriptionNow there is an image recognition problem for you. Now you are given an image which is a N * N matrix and there are only 0s and 1s in the matrix. And we are interested in the squares in whose four edges there is no 0s. So it’s your task to find how many such
squares in the image. 

InputThe first line of the input contains an integer T (1<=T<=10) which means the number of test cases. 
For each test cases, the first line is one integer N (1<=N<=1000) which is the size of the image. Then there are N lines and each line has N integers each of which is either 0 or 1. 

OutputFor each test case, please output a line which is "Case X: Y", X means the number of the test case and Y means the number of the squares we are interested in in the image. 

Sample Input

131 1 01 1 00 0 0

 

Sample Output

Case 1: 5

 

Source2012 Multi-University Training Contest 4 

Recommendzhoujiaqi2010正歸的做法應該是線段樹，沒想到用暴力過了，呵呵

#include <iostream>#include <stdio.h>#include <string.h>using namespace std;#define MAXN 1005int up[MAXN][MAXN];int lleft[MAXN][MAXN];int map[MAXN][MAXN];int fmin(int a,int b){    if(a<b)    return a;    return b;}int main(){    int n,tcase,i,j,t=1;    int ans;    scanf("%d",&tcase);    while(tcase--)    {        scanf("%d",&n);        ans=0;        memset(lleft,0,sizeof(lleft));        memset(up,0,sizeof(up));        for(i=1;i<=n;i++)            for(j=1;j<=n;j++)            {                scanf("%d",&map[i][j]);                if(map[i][j])                {                    ans++;                    lleft[i][j]=lleft[i][j-1]+1;                    up[i][j]=up[i-1][j]+1;                }                else                {                    lleft[i][j]=0;                    up[i][j]=0;                }            }        for(i=1;i<=n;i++)        {            for(j=1;j<=n;j++)            {                              int k=fmin(up[i][j],lleft[i][j]);                if(k<=1)                continue;                int temp;                for(temp=2;temp<=k;temp++)                {                    if(up[i][j-temp+1]>=temp&&lleft[i-temp+1][j]>=temp)                    {                        ans++;                                       }                }            }                  }        printf("Case %d: %d\n",t++,ans);    }    return 0;}