import java.util.Arrays;

public class Algorithm {

    public static void main(String[] args) {

        int[] weights = {1,2,3,4,5,6,7,8,9,10};
        System.out.println(new Solution().shipWithinDays(weights, 5));
    }
}

class Solution {
    public int shipWithinDays(int[] weights, int days) {

        /**
         * 最小运输量为所有货物中最重的那个，否则大于它的货物永远不能运载
         */
        int minLoad = Arrays.stream(weights).max().getAsInt();
        int maxLoad = Arrays.stream(weights).sum();

        while (minLoad < maxLoad) {

            int load = minLoad + (maxLoad- minLoad) / 2;

            if (time(weights, load) > days) {
                minLoad = load + 1;
            }
            else {
                maxLoad = load;
            }
        }

        return minLoad;
    }

    public int time(int[] weights, int load){

        int res = 0;

        /**
         * 初始船数量最少为1
         */
        int n = 1;
        int i = 0;

        while (i < weights.length) {

            /**
             * 如果货物累计重量小于等于运载量，就累计，再计算下一个货物
             */
            if (res + weights[i] <= load) {

                res += weights[i];
                i++;
            }

            /**
             * 否则当前货物不动，清空累计，再加一艘船来计算
             */
            else {
                n++;
                res = 0;
            }
        }

        return n;
    }
}

https://leetcode-cn.com/problems/capacity-to-ship-packages-within-d-days/