class Solution {
    public int largestSumAfterKNegations(int[] nums, int k) {
        Arrays.sort(nums);

        int i = 0;
        while (i < nums.length && nums[i] < 0 && k > 0) {
            nums[i] = nums[i] * -1;
            i++;
            k--;
        }

        // K大于0，表示负数已经处理完毕了，还需转换
        if (k % 2 != 0) {
            if (i == nums.length) {
                i = nums.length - 1;
            }

            if (i == 0 || (i > 0 && nums[i] < nums[i - 1])) {
                nums[i] = nums[i] * -1;
            } else {
                nums[i - 1] = nums[i - 1] * -1;
            }
        }

        int result = 0;
        for (int j = 0; j < nums.length; j++) {
            result += nums[j];
        }

        return result;
    }
}

134. 加油站 - 力扣（LeetCode） 

class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        // if (gas.length == 1 && gas[0] >= cost[0]) {
        //     return 0;
        // }

        // int[] remain = new int[gas.length];
        // int sum = 0;
        // for (int i = 0; i < remain.length; i++) {
        //     remain[i] = gas[i] - cost[i];
        //     sum += remain[i];
        // }

        // if (sum < 0) {
        //     return -1;
        // }

        // for (int i = 0; i < remain.length; i++) {
        //     if (remain[i] <= 0) {
        //         continue;
        //     }

        //     sum = remain[i];
        //     int j = i + 1;
        //     for (; sum >= 0 && j % remain.length != i; j++) {
        //         sum += remain[j % remain.length];
        //     }

        //     if (sum >= 0 && j % remain.length == i) {
        //         return i;
        //     }
        // }

        // return -1;

        for (int i = 0; i < gas.length; i++) {
            int sumGas = 0;
            int sumCost = 0;
            int j = 0;

            while (sumGas >= sumCost && j <= gas.length) {
                sumGas += gas[(i + j) % gas.length];
                sumCost += cost[(i + j) % gas.length];
                j++;
            }

            if (sumGas >= sumCost && j > gas.length) {
                return i;
            } else {
                i = i + j - 1;
            }
        }

        return -1;

    }
}

135. 分发糖果 - 力扣（LeetCode）

class Solution {
    public int candy(int[] ratings) {
        int[] result = new int[ratings.length];
        Arrays.fill(result,1);
        
        for(int i=1;i<ratings.length;i++){
            if(ratings[i] > ratings[i-1]){
                result[i] = result[i-1] +1;
            }
        }
        
        for(int j=ratings.length-2;j>=0;j--){
            if(ratings[j] >ratings[j+1]){
                if(result[j] < result[j+1]+1){
                    result[j] = result[j+1] +1;
                }
            }
        }
        
        int sum = 0;
        for(int k=0;k<ratings.length;k++){
            sum+= result[k];    
        }
        
        return sum;
    }
}