backpack1 i92

图片.png 图片.png

//i92
//my
class Solution {
public:

    int backPack(int m, vector<int> &A) {
        int ss = A.size();
        if (ss == 0)
            return 0;
        vector<vector<int>> dp(ss + 1, vector<int>(m + 1, 0));
        for (int j = 1; j <= m; j++) {
            dp[0][j] = -1;
        }

        for (int i = 1; i <= ss; i++) {
            for (int j = 0; j <= m; j++) {
                dp[i][j] = dp[i - 1][j];
                if (j - A[i - 1] >= 0 && dp[i - 1][j - A[i - 1]] != -1) {
                    dp[i][j] = max(dp[i][j], dp[i - 1][j - A[i - 1]] + A[i - 1]);
                }
            }
        }

        int ans = 0;
        for (int i = m; i >= 0; i--) {
            ans = max(ans, dp[ss][i]);
        }
        return ans;
    }
};

• 第二种方法：true or false 方法

//my
//f[i][w] = f[i-1][w] OR f[i-1][w-Ai-1]
class Solution {
public:
    int backPack(int m, vector<int> &A) {
        int ss = A.size();
        vector<vector<bool>> dp(ss + 1, vector<bool>(m + 1, false));
        dp[0][0] = true;
        for (int i = 1; i <= ss; i++) {
            for (int j = 0; j <= m; j++) {
                dp[i][j] = dp[i - 1][j];
                if (j - A[i - 1] >= 0 && dp[i - 1][j - A[i - 1]]) {
                    dp[i][j] = true;
                }
            }
        }

        for (int w = m; w >= 0; w--) {
            if (dp[ss][w] == true)
                return w;
        }
        return 0;
    }
};