• bzoj1084: [SCOI2005]最大子矩阵


    题很傻TAT

    但是我的转移很蛋疼。。。

    这么蛋疼的转移能一次写对还是佩服自己QAQ。。

    记一下这蛋疼的代码(看到黄学长O(n·(a^m)·k)的没写对,貌似还有O(n^m*k)的写法。

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<cstdlib>
      4 #include<algorithm>
      5 #include<iostream>
      6 
      7 using namespace std;
      8 
      9 void setIO(const string& s) {
     10     freopen((s + ".in").c_str(), "r", stdin);
     11     freopen((s + ".out").c_str(), "w", stdout);
     12 }
     13 template<typename Q> Q read(Q& x) {
     14     static char c, f;
     15     for(f = 0; c = getchar(), !isdigit(c); ) if(c == '-') f = 1;
     16     for(x = 0; isdigit(c); c = getchar()) x = x * 10 + c - '0';
     17     if(f) x = -x;
     18     return x;
     19 }
     20 template<typename Q> Q read() {
     21     static Q x; read(x); return x;
     22 }
     23 
     24 const int N = 100 + 10, INF = ~0u >> 1;
     25 
     26 int n, m, f[N][5][11], K, a[N][2];
     27 
     28 template<typename Q> void maxit(Q& x, const Q& y) {
     29     if(x < y) x = y;
     30 }
     31 
     32 int dp1() {
     33     for(int i = 1; i <= n + 1; i++) {
     34         for(int k = 0; k <= K; k++) {
     35             maxit(f[i][1][k], f[i-1][1][k] + a[i][0]);
     36             maxit(f[i][1][k], f[i-1][0][k] + a[i][0]);
     37             maxit(f[i][0][k], f[i-1][0][k]);
     38             if(k) maxit(f[i][0][k], f[i-1][1][k-1]);
     39         }
     40     }
     41     return f[n+1][0][K];
     42 }
     43 
     44 int dp2() {
     45     for(int i = 1; i <= n + 1; i++) {
     46         for(int k = 0; k <= K; k++) {
     47             maxit(f[i][0][k], f[i-1][0][k]);
     48             if(k) {
     49                 maxit(f[i][0][k], f[i-1][1][k-1]);
     50                 maxit(f[i][0][k], f[i-1][2][k-1]);
     51                 maxit(f[i][0][k], f[i-1][4][k-1]);
     52                 if(k >= 2) maxit(f[i][0][k], f[i-1][3][k-2]);
     53             }
     54             
     55             for(int j = 0; j < 2; j++) {
     56                 maxit(f[i][j+1][k], f[i-1][j+1][k] + a[i][j]);
     57                 maxit(f[i][j+1][k], f[i-1][0][k] + a[i][j]);
     58                 if(k) {
     59                     maxit(f[i][j+1][k], f[i-1][2-j][k-1] + a[i][j]);
     60                     maxit(f[i][j+1][k], f[i-1][4][k-1] + a[i][j]);
     61                     maxit(f[i][j+1][k], f[i-1][3][k-1] + a[i][j]);
     62                 }
     63             }
     64             maxit(f[i][3][k], f[i-1][3][k] + a[i][0] + a[i][1]);
     65             maxit(f[i][3][k], f[i-1][0][k] + a[i][0] + a[i][1]);
     66             if(k >= 2) maxit(f[i][3][k], f[i-1][4][k-2] + a[i][0] + a[i][1]);
     67             maxit(f[i][3][k], f[i-1][1][k] + a[i][0] + a[i][1]);
     68             maxit(f[i][3][k], f[i-1][2][k] + a[i][0] + a[i][1]);
     69             
     70             maxit(f[i][4][k], f[i-1][4][k] + a[i][0] + a[i][1]);
     71             maxit(f[i][4][k], f[i-1][0][k] + a[i][0] + a[i][1]);
     72             if(k) {
     73                 maxit(f[i][4][k], f[i-1][1][k-1] + a[i][0] + a[i][1]);
     74                 maxit(f[i][4][k], f[i-1][2][k-1] + a[i][0] + a[i][1]);
     75                 if(k >= 2) maxit(f[i][4][k], f[i-1][3][k-2] + a[i][0] + a[i][1]);
     76             }
     77         }
     78     }
     79     return f[n+1][0][K];
     80 }
     81 
     82 int main() {
     83 #ifdef DEBUG
     84     freopen("in.txt", "r", stdin);
     85     freopen("out.txt", "w", stdout);
     86 #endif
     87     
     88     memset(f, -0x3f, sizeof f);
     89     f[0][0][0] = 0;
     90     scanf("%d%d%d", &n, &m, &K);
     91     for(int i = 1; i <= n; i++) {
     92         for(int j = 0; j < m; j++) {
     93             scanf("%d", a[i] + j);
     94         }
     95     }
     96     if(m == 1) cout << dp1() << endl;
     97     else cout << dp2() << endl;
     98     
     99     return 0;
    100 }
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  • 原文地址:https://www.cnblogs.com/showson/p/5028367.html
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