LeetCode 42

Trapping Rain Water

Given n non-negative integers representing an elevation map where

the width of each bar is 1, compute how much water it is able to trap after raining.

For example,
Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6.

#include<stdio.h>

int trap( int* height, int heightSize ){

    int left = 0;
    int right = heightSize - 1;
    int middle = 0;
    int water = 0;

    while( left < right ){

        if( height[left] < height[right]){
            middle = middle > height[left] ? middle : height[left];
            water = water + middle - height[left];
            left ++;
        }else{
            middle = middle > height[right] ? middle : height[right];
            water = water + middle - height[right];
            right --;
        }
    }
    printf("Water is %d
", water);
    return water;
}

int main(){
    int height[] = {0,1,0,2,1,0,1,3,2,1,2,1};
    int heightSize = 12;
    trap( height, heightSize );
    return 0;
}