算法修炼Day43|1049. 最后一块石头的重量 II ● 494. 目标和

题目：leetcode.cn/problems/la…

代码实现：

class Solution {
    public int lastStoneWeightII(int[] stones) {
        int sum = 0;
        for (int num : stones) {
            sum += num;
        }
        int target = sum >> 1;
        int[] dp = new int[target + 1];

        for (int i = 0; i < stones.length; i++) {
            for (int j = target; j >= stones[i]; j--) {
                dp[j] = Math.max(dp[j], dp[j - stones[i]] + stones[i]);
            }
        }
        return sum - 2 * dp[target];
    }
}

题目：494. 目标和 - 力扣（LeetCode）

代码实现：

class Solution {
    public int findTargetSumWays(int[] nums, int target) {
        int sum = 0;
        for (int i = 0; i < nums.length; i++) sum += nums[i];
        if (target > 0 && sum < target || target < 0 && sum < -target) return 0;
        if ((target + sum) % 2 != 0) return 0;
        int size = (target + sum) / 2;
        if (size < 0) size = -size;
        int[] dp = new int[size + 1];
        dp[0] = 1;
        for (int i = 0; i < nums.length; i++) {
            for (int j = size; j >= nums[i]; j--) {
                dp[j] += dp[j - nums[i]];
            }
        }
        return dp[size];
    }
}