算法训练营第三十四天|1005.K次取反后最大化的数组和 134. 加油站 135. 分发糖果

Leetcode1005.K次取反后最大化的数组和

class Solution {
public:
    static bool cmp(int a, int b){
        return abs(a) > abs(b);
    }
    
    int largestSumAfterKNegations(vector<int>& nums, int k) {
        int res = 0;
        sort(nums.begin(), nums.end(), cmp);
        for (int i = 0; i < nums.size(); i++){
            if (nums[i] < 0 && k > 0){
                nums[i] *= -1;
                k--;
            }
        }
        if (k > 0 && k % 2 == 1) nums[nums.size() - 1] *= -1;
        for (int i : nums) res += i;
        return res;
    }
};

Leetcode134. 加油站

class Solution {
public:
    int canCompleteCircuit(vector<int>& gas, vector<int>& cost) {
        int sum = 0;
        int min = INT_MAX;
        int rest = 0;
        for (int i = 0; i < gas.size(); i++){
            rest += gas[i] - cost[i];
            if (rest < min){
                min = rest;
            }
        }
        if (rest < 0) return -1;
        if (min >= 0) return 0;
        
        for (int i = gas.size() - 1; i > 0; i--){
            min += gas[i] - cost[i];
            if (min >= 0) return i;
        }
        return false;
    }
};

Leetcode135. 分发糖果

class Solution {
public:
    int candy(vector<int>& ratings) {
        vector<int> res(ratings.size(), 1);
        for (int i = 1; i < ratings.size(); i++){
            if (ratings[i] > ratings[i - 1]) res[i] = res[i - 1] + 1;
        }
        for (int i = ratings.size() - 2; i >= 0; i--){
            if (ratings[i] > ratings[i + 1]) {
                res[i] = max(res[i], res[i + 1] + 1);
            }
        }
        int result = 0;
        for (int i : res){
            result += i;
        }
        return result;
    }
};

第三十三天休息，三十四天打卡。加油！！！