接雨水 about blog

[rottenpen]

/**
 * @param {number[]} height
 * @return {number}
 */
var trap = function(height) {
    let max = Math.max(...height)
    // let maxIndexs = []
    let l = 0
    let r = height.length - 1
    let sum = 0
    let maxIndex = height.indexOf(max)
    let lastLeft = 0
    let lastRight = 0
    // console.log(maxIndex)
    if(!height.length){
        return 0
    } else {
        while (l<r) {
            if(l !== maxIndex) {
                let ll = l ? height[l - 1] : 0
                lastLeft = lastLeft < ll ? ll: lastLeft
                let diffLeft =  lastLeft - height[l] // 左边高于下一个
                // console.log("l" + ll, lastLeft, diffLeft)
                sum = diffLeft > 0 ? sum + diffLeft : sum
                l ++;
            }
            if(r !== maxIndex) {
                let rr = r < height.length - 1 ? height[r + 1] : 0
                lastRight = lastRight < rr ? rr: lastRight
                let diffRight =  lastRight - height[r] // 左边高于下一个
                // console.log("r" + rr,r, lastRight, diffRight)
                sum = diffRight > 0 ? sum + diffRight : sum
                r --;
            }
        }
    }
    return sum  
};

终于成了