动态规划

01背包 hdu2602http://acm.hdu.edu.cn/showproblem.php?pid=2602

每个物品一个。

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<algorithm>
#define INF 0x3f3f3f3f
using namespace std;
int val[1010], vol[1010], dp[1010];
int main()
{
    int t, n, v;
    cin >> t;
    while(t--){
        memset(dp, 0, sizeof(dp));
        cin >> n >> v;
        for(int i = 0; i < n; i++){
            cin >> val[i];
        }
        for(int i = 0; i < n; i++){
            cin >> vol[i];
        }
        for(int i = 0; i < n; i++){
            for(int j = v; j >= vol[i]; j--){//从大到小
                dp[j] = max(dp[j], dp[j-vol[i]]+val[i]);
            } 
        }
        cout << dp[v] << endl;
    }
    return 0;
}

完全背包 hdu2602改成完全背包的话

每个物品无数个

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<algorithm>
#define INF 0x3f3f3f3f
using namespace std;
int val[1010], vol[1010], dp[1010];
int main()
{
    int t, n, v;
    cin >> t;
    while(t--){
        memset(dp, 0, sizeof(dp));
        cin >> n >> v;
        for(int i = 0; i < n; i++){
            cin >> val[i];
        }
        for(int i = 0; i < n; i++){
            cin >> vol[i];
        }
        for(int i = 0; i < n; i++){
            for(int j = vol[i]; j <= v; j++){
                dp[j] = max(dp[j], dp[j-vol[i]]+val[i]);
            } 
        }
        cout << dp[v] << endl;
    }
    return 0;
}

 最长公共子序列LCS poj1458http://poj.org/problem?id=1458

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<vector>
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
#define IO ios::sync_with_stdio(false);cin.tie(0);
#define INF 1e9
#define MAXN 1010
const int MOD=1e9+7;
typedef long long ll;
using namespace std;
char a[MAXN], b[MAXN];
int dp[MAXN][MAXN];
int main()
{
    while(cin >> a+1 >> b+1){
        memset(dp, 0, sizeof(dp));
        int la = strlen(a+1), lb = strlen(b+1);
        for(int i = 1; i <= la; i++){
            for(int j = 1; j <= lb; j++){
                if(a[i] == b[j]){
                    dp[i][j] = dp[i-1][j-1]+1;
                }
                else{
                    dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
                }
            }
        } 
        cout << dp[la][lb] << endl;
    }
    return 0;
}