// 962. Maximum Width Ramp #include "leetcode.h" /* * a ramp in an integer array 'nums' is a pair '(i, j)' for which 'i < j' and * 'nums[i] <= nums[j]'. the width of such ramp is 'j - i'. given an integer * array 'nums', return the maximum width of a ramp in 'nums' if there is no * ramp in 'nums', return 0 */ int maxWidthRamp(int *nums, int numsSize) { int ans = 0, idx = 0; int *stack = (int *)malloc(numsSize * sizeof(int)); for (int i = 0; i < numsSize; i++) { if (!idx) stack[idx++] = i; else { if (nums[i] <= nums[stack[idx - 1]]) stack[idx++] = i; } } for (int i = numsSize - 1; i >= 0; i--) while (idx && nums[i] >= nums[stack[idx - 1]]) ans = fmax(ans, i - stack[--idx]); free(stack); return ans; } int main() { int n1[] = {6, 0, 8, 2, 1, 5}, n2[] = {9, 8, 1, 0, 1, 9, 4, 0, 4, 1}; printf("%d\n", maxWidthRamp(n1, ARRAY_SIZE(n1))); // expect: 4 printf("%d\n", maxWidthRamp(n2, ARRAY_SIZE(n2))); // expect: 7 }