Elevator

怎麽今天寫啥題都不會寫啊， 我是傻了嗎。。

把電梯裏面四個人的目標點當作狀態， 然後暴力轉移。

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define
 
 ull unsigned long long

using namespace std;

const int N = 2000 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
const double eps = 1e-8;
const double PI = acos(-1);

int dp[2][10][10][10][10][10];
int n, a[N], b[N];
int cur = 0, lst = 1;

inline bool
 
 chkmin(int &a, int b) {
    return a > b ? a = b, true : false;
}

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) scanf("%d%d", &a[i], &b[i]);
    memset(dp[cur], inf, sizeof(dp[cur]));
    dp[cur][1][0][0][0][0] = 2 * n;
    for(int i = 0; i <= n; i++) {
        swap(cur, lst);
        memset(dp[cur], inf, 
 
sizeof(dp[cur]));
        for(int c1 = 9; c1 >= 0; c1--) {
            for(int c2 = 9; c2 >= 0; c2--) {
                for(int c3 = 9; c3 >= 0; c3--) {
                    for(int c4 = 9; c4 >= 0; c4--) {
                        for(int f = 1; f <= 9; f++) {
                            int& ret = dp[lst][f][c1][c2][c3][c4];
                            if(ret >= inf) continue;
                            if(!c1 && i < n) {
                                chkmin(dp[cur][a[i + 1]][b[i + 1]][c2][c3][c4], ret + abs(f - a[i + 1]));
                            } else if(c1) {
                                chkmin(dp[lst][c1][0][c2][c3][c4], ret + abs(f - c1));
                            }
                            if(!c2 && i < n) {
                                chkmin(dp[cur][a[i + 1]][c1][b[i + 1]][c3][c4], ret + abs(f - a[i + 1]));
                            } else if(c2) {
                                chkmin(dp[lst][c2][c1][0][c3][c4], ret + abs(f - c2));
                            }
                            if(!c3 && i < n) {
                                chkmin(dp[cur][a[i + 1]][c1][c2][b[i + 1]][c4], ret + abs(f - a[i + 1]));
                            } else if(c3) {
                                chkmin(dp[lst][c3][c1][c2][0][c4], ret + abs(f - c3));
                            }
                            if(!c4 && i < n) {
                                chkmin(dp[cur][a[i + 1]][c1][c2][c3][b[i + 1]], ret + abs(f - a[i + 1]));
                            } else if(c4) {
                                chkmin(dp[lst][c4][c1][c2][c3][0], ret + abs(f - c4));
                            }
                        }
                    }
                }
            }
        }
    }
    int ans = inf;
    for(int i = 1; i <= 9; i++)
        ans = min(ans, dp[lst][i][0][0][0][0]);
    printf("%d\n", ans);
    return 0;
}

/*
*/

Codeforces 983C Elevator dp (看題解)