动态规划01背包问题关于状态转移方程。

#include <stdio.h>  
#include <tchar.h>  
#include <queue>  
#include "iostream"  
  
using namespace std;  
  
const int N = 4;  
const int W = 5;  
int weight[N] = {2, 1, 3, 2};  
int value[N] = {3, 2, 4, 2};  
int record[N][W];  
void init()  
{  
    for(int i = 0; i < N; i ++)  
    {  
        for(int j = 0; j < W; j ++)   
        {  
            record[i][j] = -1;  
        }  
    }  
}  
  
int solve(int i, int residue)   
{  
    if(-1 != record[i][residue])  
        return record[i][residue];  
    int result = 0;  
    if(i >= N)  
        return result;  
    if(weight[i] > residue)  
    {  
        record[i + 1][residue] = solve(i+1, residue);  
         
    }  
    else   
    {  
        result = max(solve(i+1, residue), solve(i+1, residue-weight[i]) + value[i]);  
    }  
    return record[i + 1][residue] = result;  
}  
  
int main() {  
    init();  
    int result = solve(0, W);  
    cout << result << endl;  
    return 0;  
}