【NOIP2001】【Luogu1030】求先序排列

problem

solution

codes

#include<stdio.h>
#include<string.h>
#define maxn 10
#define maxv maxn*30
char in[maxn], post[maxn];
char lch[maxv], rch[maxv];
int build(int l1, int r1, int l2, int r2){
    if(l1 > r1)return 0;
    char root = post[r2];
    int p = l1; while(in[p] != root)p++;
    int cnt = p-l1;
    lch[root] = build(l1,p-1,l2,l2+cnt-1);
    rch[root] = build(p+1,r1,l2+cnt,r2-1);
    return (int)root;
}
void dfs(char root){
    printf("%c",root);
    if(lch[root])dfs(lch[root]);
    if(rch[root])dfs(rch[root]);
}
int main(){
    scanf("%s%s",in+1,post+1);
    int n = strlen(in+1);
    build(1,n,1,n);
    dfs(post[n]);
    return 0;
}

  

 

  
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文章来源: gwj1314.blog.csdn.net，作者：小哈里，版权归原作者所有，如需转载，请联系作者。

原文链接：gwj1314.blog.csdn.net/article/details/80601386