// 1504. Count Submatrices With All Ones #include "leetcode.h" /* * given an 'm x n' binary matrix 'mat', return the number of submatrices that * have all ones. */ int numSubmat(int **mat, int matSize, int *matColSize) { int m = matColSize[0], ans = 0; int *dp = (int *)calloc(m, sizeof(int)); for (int i = 0; i < matSize; i++) { for (int j = 0; j < m; j++) dp[j] = mat[i][j] ? dp[j] + 1 : 0; int *sum = (int *)calloc(m, sizeof(int)); int *stack = (int *)malloc(m * sizeof(int)), top = -1; for (int j = 0; j < m; j++) { while (top >= 0 && dp[stack[top]] >= dp[j]) top--; if (top >= 0) { int curr = stack[top]; sum[j] = sum[curr] + dp[j] * (j - curr); } else sum[j] = dp[j] * (j + 1); stack[++top] = j; ans += sum[j]; } free(sum), free(stack); } free(dp); return ans; } int main() { int m1i[3][3] = {{1, 0, 1}, {1, 1, 0}, {1, 1, 0}}, m2i[3][4] = {{0, 1, 1, 0}, {0, 1, 1, 1}, {1, 1, 1, 0}}; struct two_d_arr *m1 = two_d_arr_init(ARRAY_SIZE(m1i), ARRAY_SIZE(m1i[0]), m1i); struct two_d_arr *m2 = two_d_arr_init(ARRAY_SIZE(m2i), ARRAY_SIZE(m2i[0]), m2i); printf("%d\n", numSubmat(m1->arr, m1->row_size, m1->col_size)); // expect: 13 printf("%d\n", numSubmat(m2->arr, m2->row_size, m2->col_size)); // expect: 24 two_d_arr_free(m1); two_d_arr_free(m2); }