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#include <bits/stdc++.h> |
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using namespace std; |
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int n, m, ans, area, v[105][105]; |
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int main(){ |
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while(scanf("%d %d", &n, &m), n | m){ |
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for(int i = 1; i <= n; i++) |
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for(int j = 1; j <= m; j++) |
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scanf("%d", &v[i][j]), v[i][j] += v[i - 1][j] + v[i][j - 1] - v[i - 1][j - 1]; |
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ans = 0; |
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for(int i = 1; i <= n; i++) |
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for(int j = 1; j <= m; j++) |
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for(int ii = i; ii <= n; ii++) |
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for(int jj = j; jj <= m; jj++){ |
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if((ii - i + 1) * (jj - j + 1) > ans){ |
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area = v[ii][jj] - v[ii][j - 1] - v[i - 1][jj] + v[i - 1][j - 1]; |
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if(area == 0) ans = (ii - i + 1) * (jj - j + 1); |
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} |
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} |
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printf("%d\n", ans); |
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} |
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return(0); |
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} |
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