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#include <iostream>
#include <vector>

class Solution {
public:
    int shipWithinDays(std::vector<int>& weights, int days) {
        int left = 0, right = 0;
        for (int w : weights) {
            left = std::max(left, w);
            right += w;
        }
        
        if (days >= weights.size()) {
            return left;
        }
        
        for (int mid = (left + right) / 2; right > left;) {
            if (check(weights, days, mid)) {
                right = mid;
            }
            else {
                left = mid + 1;
            }
            mid = (left + right) / 2;
        }
        
        return left;
    }
    
private:
    bool check(std::vector<int>& weights, int days, int cap) {
        int cur = 0;
        
        for (int weight : weights) {
            cur += weight;
            if (cur > cap) {
                cur = weight;
                if (!(--days)) {
                    return false;
                }
            }
        }
        
        return true;
    }
};