标签:mem set include stream tin 技巧 while false ast
二进制状压练得挺熟, 但是一直没有时间好好研究三进制状压。
于是找了个题目学习了一下, 两天里修修补补总算AC了。
有几个收获。
1. 三进制与十进制的转换的小技巧(利用数组)
2. 刷表法时, 用dfs来更新状态。这种更新状态的方式蛮新颖的,我这种蒟蒻第一次遇见。
3. 还是更新状态。可以先把新状态算出来,再来枚举决策。
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int MAXN = 150 + 5;
const int MAXM = 10 + 2;
int N, M, K;
bool badp[MAXN][MAXM];
int p[12] = {1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 59049};
int f[2][60000];
inline int threetoten(int a[]){
int tmp = 0;
for(int i = 0; i < M; i++)
tmp += a[i] * p[i];
return tmp;
}
inline void tentothree(int x, int a[]){
for(int i = 0; i < M; i++)
a[i] = x % 3, x /= 3;
}
int pre[13], cur[13];
void dfs(int d, int j, int last, int state)
{
int k;
f[d][state] = max(f[d][state], last);
if(j >= M) return ;
if((j + 1) < M && (pre[j] == 0) && (pre[j + 1] == 0) && (cur[j] == 0) && (cur[j + 1] == 0)){
cur[j] = cur[j + 1] = 2;
k = threetoten(cur);
dfs(d, j + 2, last + 1, k);
cur[j] = cur[j + 1] = 0;
}
if((j + 2) < M && (cur[j] == 0) && (cur[j + 1] == 0) && (cur[j + 2] == 0)){
cur[j] = cur[j + 1] = cur[j + 2] = 2;
k = threetoten(cur);
dfs(d, j + 3, last + 1, k);
cur[j] = cur[j + 1] = cur[j + 2] = 0;
}
dfs(d, j + 1, last, state);
return ;
}
int solve()
{
int d = 0; int tmp;
memset(f[d], -1, sizeof(f[d]));
for(int i = 0; i < M; i++) pre[i] = (badp[1][i] ? 2 : 1);
tmp = threetoten(pre);
f[d][tmp] = 0;
for(int i = 2; i <= N; i++){
d ^= 1;
memset(f[d], -1, sizeof(f[d]));
for(int j = 0; j < p[M]; j++){
if(f[d ^ 1][j] == -1) continue;
tentothree(j, pre);
for(int k = 0; k < M; k++){
if(badp[i][k]) cur[k] = 2;
else cur[k] = (pre[k] == 0 ? 0 : pre[k] - 1);
}
tmp = threetoten(cur);
dfs(d, 0, f[d ^ 1][j], tmp);
}
}
int ans = 0;
for(int i = 0; i < p[M]; i++) ans = max(ans, f[d][i]);
return ans;
}
int main()
{
int T; cin>>T;
while(T--)
{
cin>>N>>M>>K;
memset(badp, false, sizeof(badp));
for(int i = 1, x, y; i <= K; i++){
scanf("%d%d", &x, &y);
badp[x][y - 1] = true;
}
printf("%d\n", solve());
}
return 0;
}
标签:mem set include stream tin 技巧 while false ast
原文地址:https://www.cnblogs.com/wsmrxc/p/9281425.html