牛客小白月赛1 G あなたの蛙は旅⽴っています【DP】

题目链接

https://www.nowcoder.com/acm/contest/85/G

思路

按照题解上的方式 存取数据

然后DP一下 就可以了

AC代码

#include <cstdio>
#include <cstring>
#include <ctype.h>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <map>
#include <stack>
#include <set>
#include <numeric>
#include <sstream>
#include <iomanip>
#include <limits>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

const double PI  = 3.14159265358979323846264338327;
const double E   = exp(1);
const double eps = 1e-6;

const int INF    = 0x3f3f3f3f;
const int maxn   = 3e3 + 5;
const int MOD    = 1e9 + 7;

int Map[maxn][maxn], Cur[maxn], dp[maxn][maxn];

int main()
{
    int n;
    scanf("%d", &n);
    memset(Map, 0xc0, sizeof(Map));
    memset(Cur, 0, sizeof(Cur));
    memset(dp, 0, sizeof(dp));
    int vis = 1 + (4 * (n - 1));
    int cur = 2 * n - 1;
    int i, j;
    for (i = 0; i < n; i++)
        Cur[i] = i + 1;
    int opt[2];
    opt[i % 2] = n - 1;
    opt[!(i % 2)] = n;
    int flag = i % 2;;
    for ( ; i < (vis - n); i++, flag = !flag)
        Cur[i] = opt[flag];
    for (j = n ; i < vis; i++, j--)
        Cur[i] = j;
    vector <int> v[vis];
    int temp;
    for (i = 0; i < vis; i++)
    {
        for (j = 0; j < Cur[i]; j++)
        {
            scanf("%d", &temp);
            v[i].push_back(temp);
        }
    }
    int len = cur/2 + 1;
    flag = 0;
    for (i = 0, j = n; i < len; i++, j++)
    {
        for (int l = 0, k = flag; l < j; l++, k++)
        {
            Map[i][l] = v[k][v[k].size() - 1];
            v[k].pop_back();
            if (v[k].size() == 0)
                flag++;
        }
    }
    for (j -= 2; i < cur; i++, j--)
    {
        for (int l = (cur - j), k = flag; l < cur; l++, k++)
        {
            Map[i][l] = v[k][v[k].size() - 1];
            v[k].pop_back();
            if (v[k].size() == 0)
                flag++;
        }
    }
    dp[0][0] = Map[0][0];
    for (i = 1; i < cur; i++)
    {
        dp[0][i] = dp[0][i - 1] + Map[0][i];
        dp[i][0] = dp[i - 1][0] + Map[i][0];
    }
    for (i = 1; i < cur; i++)
    {
        for (j = 1; j < cur; j++)
            dp[i][j] = max(max(dp[i - 1][j], dp[i][j - 1]), dp[i - 1][j - 1]) + Map[i][j];
    }
    cout << dp[cur - 1][cur - 1] << endl;
}