code1064 Insect Food Calculation

DFS searches for numbers corresponding to each letter

Pruning:

1. When a column of three number a B c is known, if (a+b)%n!=c && (a+b+1)%n!=c pruning (+1 is to consider carry, attention &&)

2. Taking into account that we are pruning according to each row of data, we can change the order of the search, according to the letter from the top down, from the right to the left to appear in the order to search

3. Because we are starting from the lowest bit, and, 3 numbers are all n-bit, so the high-level array is generally small, low-large, so should be from the n-1 upside down (the high is too large and not n-bit)

Code:

#include <iostream>#include<cstdlib>#include<cstring>#defineSize 30using namespacestd;intN;intcc[3][size];intdic[size]={0,1,0,3,4,2};BOOLVis[size];BOOLRowinti) {    if(dic[cc[0][i]]!=-1&&dic[cc[1][i]]!=-1&&dic[cc[2][i]]!=-1){        intk=dic[cc[0][i]]+dic[cc[1][i]]; if(k%n!=dic[cc[2][i] && (k +1)%n!=dic[cc[2][i]])return false; }    return true;}intNext () { for(intI=1; i<=n;i++){         for(intj=0;j<3; j + +){            if(dic[cc[j][i]]==-1)returnCc[j][i]; }    }    returnn+1;}BOOLCheck () {intdd[3][size];  for(intI=0;i<3; i++){         for(intj=1; j<=n;j++) {Dd[i][j]=Dic[cc[i][j]]; }    }    intF[size]; Memset (F,0,sizeof(f));  for(intI=1; i<=n;i++) {F[i]+=dd[0][i];f[i]+=dd[1][i];  while(f[i]>=n) f[i]-=n,f[i+1]++; if(f[i]!=dd[2][i])return false; }    return true;}voidDfsintk) {    if(k>N) {        if(check ()) { for(intI=1; i<=n;i++) cout<<dic[i]<<' '; Exit (0); }    }    //Jianzhi     for(intI=1; i<=n;i++) {//1        if(!row (i))return; }         for(inti=n-1; i>=0; i--){        if(!Vis[i]) {Dic[k]=i; Vis[i]=true;            DFS (next ()); Vis[i]=false; DIC[K]=-1; }    }}intMain () {Freopen ("1064.in","R", stdin); memset (DIC,-1,sizeof(DIC)); CIN>>N; CharTemp[size];  for(intI=0;i<3; i++) {cin>>temp+1;  for(intj=1; j<=n;j++) {Cc[i][j]=temp[n-j+1]- -;    }} dfs (next ()); return 0;} 

Test point #alpha1.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha10.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha2.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha3.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha4.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha5.in Results:ACMemory usage: 256kB time consumption: 1ms
Test point #alpha6.in Results:ACMemory usage: 256kB time consumption: 31ms
Test point #alpha7.in Results:ACMemory usage: 256kB time consumption: 3ms
Test point #alpha8.in Results:ACMemory usage: 256kB time consumption: 78ms
Test point #alpha9.in Results:ACMemory usage: 256kB time consumption: 1ms

code1064 Insect Food Calculation