Nine degree 1497: the largest full 1 sub-matrix of the area

Title Description:

In a matrix of M * N, all elements are only 0 and 1, from this matrix to find an area of the largest total 1 sub-matrix, the so-called maximum refers to the number of elements 1 the most.

input:

For each test case, the first line entered is two integers m, n (1<=m, n<=1000): Represents the size of the matrix that will be entered. The
Matrix has m rows, each row has n integers, 0 or 1, respectively, separated by a single space between the two adjacent numbers.

Output:

Corresponds to each test case, the number of elements in the output matrix of the largest total 1 sub-matrices.

Sample input:

2 20 00 04 40 0 0 00 1 1 00 1 1 00 0 0 0

Sample output:

04

Count the 1 consecutive numbers in each row

For example

1 1 1 1 1 0 1

0 0 1 1 1 0 1

1 1 0 0 1 0 0

Get

1 2 3 4 5 0 1

0 0 1 2 0 1 1

0 0 1 2 3 0 1

1 2 0 0 1 0 0

And then follow the column accumulation to get continuous

1 2 5 8 5 0 3

0 0 5 8 0 1 3

0 0 5 8 4 0 3

1 2 0 0 4 0 0

This is done by comparing it with the MAXN to see if it counts.

Then if there is a need to calculate, then look at this position down and go online, find in the case of the second rectangle this column is small to this number when the exit

Because this number is the number of 1 of the horizontal over the statistic

The 1 matrix can be built at the present length only when it is greater than or equal to itself.

So get the code as follows

#include <stdio.h> #include <string.h> #include <algorithm>using namespace Std;int map[1005][1005];    int col[1005][1005];int n,m,maxn;void set_col (int p) {int i,j,sum;        for (i = 1; i<=n; i++) {if (!map[i][p]) continue;        j = i;        sum = 0;            while (Map[j][p] && j<=n) {sum+=map[j][p];        j + +;        } for (int k = i; k<j; k++) col[k][p] = sum;    i = j;    }}int Find (int r,int c) {int i,j,val=map[r][c];    int cnt = 1;        for (i = r-1; i>0; i--) {if (val>map[i][c]) break;    cnt++;        } for (i = r+1; i<=n; i++) {if (val>map[i][c]) break;    cnt++; } return val*cnt;}    int solve () {int i,j;    MAXN = 0; for (i = 1; i<=n; i++) {for (j = 1; j<=m; j + +) {if (Maxn<col[i][j] && map[i][j                ]) {int val = find (i,j); MAXN = max(Maxn,val); }}} return MAXN;}    int main () {int i,j;                while (~SCANF ("%d%d", &n,&m)) {for (i = 1; i<=n; i++) {for (j = 1; j<=m; j + +)        scanf ("%d", &map[i][j]);  } for (i = 1; i<=n; i++) {for (j = 2; j<=m; j + +) {if (map[i][j]==1            && map[i][j-1]) map[i][j]=map[i][j-1]+1;        }} for (i = 1; i<=m; i++) Set_col (i);    printf ("%d\n", Solve ()); } return 0;}

Nine degree 1497: the largest full 1 sub-matrix of the area