Question

一道acm水编程题，高分求解答，解答后加加悬赏分

Problem B: Count the rectangles
Time Limit:1 Sec Memory Limit:128 MB
Submit:24 Solved:7
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Description
You are given numbers of rectangles made of '1's and '0's.Calculate how many small rectangles which have four '1's on the four corners.

Input

There are several test cases, each test case starts with a line containing two positive integers n and m. n and m is the size of the rectangle (1<=n<=100, 1<=m<=100). Next follow a rectangle which contains only number '0' and '1'. The input will finish with the end of file.

Output
The number of rectangles which meet the requirements.

Sample Input
3 4
1 0 1 0
0 1 1 0
1 1 1 0

Sample Output
2

说一下思路就行了
就是输入一个矩阵 求出这个矩阵包含多少个小矩阵 小矩阵的四周都为1

Answer 1

先枚举两行，然后统计一下这两行中对应的例中都是1的个数，然后再用

组合数c(cnt,2)算出这两行中四个角都是1的种数。
总复杂度是n*n*m