poj 1050

省赛前练习点动态规划

#include <iostream>
#include <algorithm>
#include <queue>
#include <cstring>
#include <cstdio>
#include <vector>
#include <string>
#include <iterator>
#include <cmath>
#include <deque>
#include <stack>
#include <cctype>
#include <iomanip>
using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 110;
const int INF = 0xfffffff;
const double EPS = 1e-8;
const ll MOD = 1e9 + 7;
const ld PI = acos (-1.0);

#define INFL 0x7fffffffffffffffLL
#define met(a, b) memset(a, b, sizeof(a))
#define put(a) cout << setiosflags(ios::fixed) << setprecision(a)

int n, a[N][N], dp[N];

int solve ()
{
    int sum = 0, maxn = -INF;
    for (int i=0; i<n; i++)
    {
        sum += dp[i];
        if (sum < 0) sum = 0;
        maxn = max (sum, maxn);
    }
    return maxn;
}

int main ()
{

    while (cin >> n)
    {
        met (a, 0);
        met (dp, 0);
        for (int i=0; i<n; i++)
            for (int j=0; j<n; j++)
                cin >> a[i][j];
        int ans = -INF;
        for (int i=0; i<n; i++)
        {
            met (dp, 0);
            for (int j=i; j<n; j++)
            {
                for (int k=0; k<n; k++)
                    dp[k] += a[j][k];
                ans = max (ans, solve());
            }
        }
        cout << ans << endl;
    }
    return 0;
}

#include <iostream>
#include <algorithm>
#include <queue>
#include <cstring>
#include <cstdio>
#include <vector>
#include <string>
#include <iterator>
#include <cmath>
#include <deque>
#include <stack>
#include <cctype>
#include <iomanip>
using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 110;
const int INF = 0xfffffff;
const double EPS = 1e-8;
const ll MOD = 1e9 + 7;
const ld PI = acos (-1.0);

#define INFL 0x7fffffffffffffffLL
#define met(a, b) memset(a, b, sizeof(a))
#define put(a) cout << setiosflags(ios::fixed) << setprecision(a)

int n, a[N][N], dp[N][N][N];

int main ()
{

    while (cin >> n)
    {
        met (a, 0); met (dp, 0);
        for (int i=1; i<=n; i++)
            for (int j=1; j<=n; j++)
            cin >> a[i][j];
        int ans = -INF;
        for (int i=1; i<=n; i++)
        {
            for (int j=1; j<=n; j++)
            {
                int sum = 0;
                for (int k=j; k<=n; k++)
                {
                    sum += a[i][k];
                    dp[i][j][k] = max (dp[i-1][j][k] + sum, sum);
                    ans = max (dp[i][j][k], ans);
                }
            }
        }
        cout << ans << endl;
    }
    return 0;
}