在 D 天内送达包裹的能力

　　 

 　　这题和之前做的一个滴滴魔法石题很像。解题步骤也基本一致  由于最低运力肯定是大于等于最大货物重量，小于等于所有货物相加的重量。所以直接二分查找  复杂度应该是NlogN

　　

class Solution {
    public int shipWithinDays(int[] weights, int D) {
        int total = 0;
        int max = 0;
        for (int weight : weights) {
            total+=weight;
            max = Math.max(weight,max);
        }
        int left = max,right = total;
        //二分法查看是否满足
        while (left<right){
            int mid = (left+right)/2;
            if (check(weights, D, mid)){
                right = mid;
            }else {
                left = mid+1;
            }
        }
         return left;
    }

    public boolean check(int[] weights,int D,int mid){
          int s = 0;
        int tpt = 0;
        for (int i = 0; i < weights.length; i++) {
            int t = weights[i];
            tpt+=t;
            if (tpt == mid){
                s++;
                tpt = 0;
            }else if (tpt > mid){
                s++;
                tpt = t;
            }
            if (s >D){
                return false;
            }
            if (i == weights.length-1 && tpt != 0){
                s++;
            }
        }

        return s<=D;
    }
}