hdu 1057 (simulation, use sentinel to avoid boudary testing, use swap trick to avoid extra copy.） 分类： hdoj 2015-06-19 11:58 25人阅读 评论(0) 收藏

use sentinel to avoid boudary testing,
use swap trick to avoid extra copy.
original version

#include <cstdio>
#include <algorithm>

int main() {
    //freopen("input.txt","r",stdin);
    const int MAXSIZE=22, dimSize=20;
    int bacnums1[MAXSIZE][MAXSIZE]={0},bacnums2[MAXSIZE][MAXSIZE]={0}, (*now)[MAXSIZE]=bacnums1, (*next)[MAXSIZE]=bacnums2, dna[16];
    int ncase, nday, i,j,tmp;
    if(scanf("%d",&ncase)!=1 || ncase<=0) return -1;
    while(ncase--) {
        scanf("%d",&nday);
        for(i=0;i<16;++i) scanf("%d",&dna[i]);
        for(i=1;i<=dimSize;++i)
        for(j=1;j<=dimSize;++j)
        scanf("%d",&now[i][j]);
        while(nday-->0) {
            for(i=1;i<=dimSize;++i)
            for(j=1;j<=dimSize;++j) {
                tmp=now[i][j]+now[i-1][j]+now[i+1][j]+now[i][j-1]+now[i][j+1];
                next[i][j]=now[i][j]+dna[tmp];
                if(next[i][j]<0) { next[i][j]=0; }
                else if(next[i][j]>3) { next[i][j]=3; }
            }
            std::swap(now,next);
        }
        for(i=1;i<=dimSize;++i) {
            for(j=1;j<=dimSize;++j)
            switch(now[i][j]) {
            case 0: putchar('.'); break;
            case 1: putchar('!'); break;
            case 2: putchar('X'); break;
            case 3: putchar('#'); break;
            default: break;
            }
            putchar('
');
        }
        if(ncase) putchar('
');
    }
    return 0;
}

version 2, fgets + parsing, write to a buffer then output,
since the lines are quite short, there is no performance improvement.

#include <cstdio>
#include <algorithm>

int main() {
    //freopen("input.txt","r",stdin);
    const int MAXSIZE=22, dimSize=20, lineMaxSize=500;
    int bacnums1[MAXSIZE][MAXSIZE]={0},bacnums2[MAXSIZE][MAXSIZE]={0}, (*now)[MAXSIZE]=bacnums1, (*next)[MAXSIZE]=bacnums2, dna[16];
    char line[lineMaxSize],output[lineMaxSize], *pc;
    int ncase, nday, i,j,tmp, *p, *pend;
    if(scanf("%d",&ncase)!=1 || ncase<=0) return -1;
    while(ncase--) {
        scanf("%d
",&nday);
        pc=fgets(line,lineMaxSize,stdin);
        for(p=dna,pend=dna+16;p!=pend;++p) {
            for(;*pc==' ';++pc) ;
            if(*pc=='-') { tmp='0'-*++pc; }
            else { tmp=*pc-'0'; }
            ++pc; *p=tmp;
        }
        for(i=1;i<=dimSize;++i) {
            pc=fgets(line,lineMaxSize,stdin);
            for(p=&now[i][1],pend=p+dimSize;p!=pend;++p) {
                for(;*pc==' ';++pc) ;
                *p=*pc++ -'0';
            }
        }
        while(nday-->0) {
            for(i=1;i<=dimSize;++i)
            for(j=1;j<=dimSize;++j) {
                tmp=now[i][j]+now[i-1][j]+now[i+1][j]+now[i][j-1]+now[i][j+1];
                next[i][j]=now[i][j]+dna[tmp];
                if(next[i][j]<0) { next[i][j]=0; }
                else if(next[i][j]>3) { next[i][j]=3; }
            }
            std::swap(now,next);
        }
        for(pc=output, i=1;i<=dimSize;++i) {
            for(j=1;j<=dimSize;++j)
            switch(now[i][j]) {
            case 0: *pc++='.'; break;
            case 1: *pc++='!'; break;
            case 2: *pc++='X'; break;
            case 3: *pc++='#'; break;
            default: break;
            }
            *pc++='
';
        }
        if(ncase) *pc=0; else *(pc-1)=0;
        puts(output);
    }
    return 0;
}

版权声明：本文为博主原创文章，未经博主允许不得转载。// p.s. If in any way improment can be achieved, better performance or whatever, it will be well-appreciated to let me know, thanks in advance.