算法训练营day44

题目1：二维dp数组求 01 背包46. 携带研究材料（第六期模拟笔试） (kamacoder.com)

#include<iostream>
#include<vector>

using namespace std;

int main() {
    int n,bagweight;
    cin >> n >> bagweight;
    vector<int> weight(n);
    vector<int> val(n);
    for(int i = 0;i < n;i++) {
        cin >> weight[i];
    }
    for(int i = 0;i < n;i++) {
        cin >> val[i];
    }
    vector<vector<int>> dp(n, vector<int>(bagweight + 1, 0));
    for(int i = 0;i < n;i++) {
        dp[i][0] = 0;
    }
    for(int i = weight[0];i < bagweight + 1;i++) {
        dp[0][i] = val[0];
    }
    for(int i = 1;i < n;i++) {
        for(int j = 0;j <= bagweight;j++) {
            if(j < weight[i]) dp[i][j] = dp[i - 1][j];
            else dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - weight[i]] + val[i]);
        }
    }
    cout << dp[n - 1][bagweight] << endl;
    return 0;
}

题目2：一维dp数组求背包\

题目3：416. 分割等和子集 - 力扣（LeetCode）

class Solution {
public:
    bool canPartition(vector<int>& nums) {
        int sum = 0;
        for(int i = 0;i < nums.size();i++) {
            sum += nums[i];
        }
        if(sum % 2 == 1) return false;
        int target = sum / 2;
        vector<int> dp(target + 1, 0);
        for(int i = 0;i < nums.size();i++) {
            for(int j = target;j >= nums[i];j--) {
                dp[j] = max(dp[j], dp[j - nums[i]] + nums[i]);
            }
        }
        return dp[target] == target ? true : false;
    }
};