sicily 2010 H number

来源：互联网发布：大虾是什么意思网络语编辑：程序博客网时间：2024/04/28 22:08

解释：根据规则构造数字，而不是从头遍历一遍判断，这样可以避免很多不必要的计算。

运行效率：0秒，312KB。

代码如下，类似广度优先搜索：

#include<stdio.h>#include<string.h>#include <iostream>#include<queue>using namespace std;//int toInt(char c){ return c-'0'; }//char toChar(int i){ return i+'0'; }struct Node{Node* pre;int pos;char self;Node():pos(-1),pre(NULL){}};int getNcount(int n){char strNum[10];int ret = 0;sprintf(strNum,"%d",n);int len = strlen(strNum);queue<Node*> Q;queue<Node*> Mem;for(char i = '1'; i <= strNum[0]; i++){Node* n = new Node;n->self = i;n->pos = 0;Q.push(n);Mem.push(n);}while(!Q.empty()){Node* front = Q.front();Q.pop();if(front->pos == len-1){ret++;// char res[10];// Node* tmp = front;// int ide = 0;// while(tmp != NULL)// {// res[ide++]=tmp->self;// tmp = tmp->pre;// }// for(int i = ide-1; i >=0; i--)// cout << res[i];// cout << ' ';}else{if(front->pre == NULL){char bound = '9';if(front->self == strNum[0]){bound = strNum[1];}for(char s = '0'; s <= bound; s++){Node* n = new Node;n->self = s;n->pos = front->pos+1;n->pre = front;Q.push(n);Mem.push(n);}}else{int sign[3][2] = {{1,1},{1,-1},{-1,1}};bool duplicateTest[10]={false};for (int k = 0; k < 3; k++){int selfInt = sign[k][0]*(front->pre->self-'0')+sign[k][1]*(front->self-'0');if(selfInt < 0 || selfInt > 9){continue;}if(duplicateTest[selfInt] == true)continue;elseduplicateTest[selfInt] = true;Node* n = new Node;n->pre = front;n->pos = front->pos+1;n->self = selfInt+'0';Node* tmp = n->pre;bool canPush = false;if(n->self <= strNum[n->pos])canPush = true;else{while(tmp != NULL){if(tmp->self < strNum[tmp->pos]){canPush = true;break;}tmp = tmp->pre;}}if(canPush){Q.push(n);Mem.push(n);}else{delete n;}}}}}while (!Mem.empty()){Node* front = Mem.front();Mem.pop();delete front;}return ret;}int main(){int N;while(cin >> N){if(N < 100){cout << N << endl;continue;}int count = 0;count = getNcount(N);char str[10];sprintf(str,"%d",N);int len = strlen(str);len--;while(len > 2){char tmp[10];int i;for(i = 0; i < len; i++)tmp[i] = '9';tmp[i]='\0';int n;sscanf(tmp,"%d",&n);count += getNcount(n);len--;}if(len == 2)count += 99;cout << count << endl;}}

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