( 设计高效算法 ) 年龄排序 Age Sort Uva 11462

可以使用整数排序法, 内存太小无法堆排序.

#include <cstdio>
#include <cstring>
using namespace std;int main(){unsigned int age[101];int n,temp;while (scanf("%d", &n) == 1 && n){memset(age, 0, sizeof(age));for (int i = 0; i < n; i++){scanf("%d", &temp);age[temp]++;}bool first = 1;for (int i = 1; i < 101; i++){for (int j = 0; j < age[i];j++){if (!first) printf("");else first = false;printf("%d", i);}}printf("\n");}}

优化输入输出也可以提高效率,  但是这个是最后考虑的优化要素.

函数名前 的inline 相当于c的宏定义,  降低大量函数引用消耗的时间.

使用cctype 中的 isdigit

#include <cstdio>
#include <cstring>
#include <cctype>
using namespace std;inline int readint(){char c = getchar();while (!isdigit(c)) c = getchar();unsigned int num = 0;while (isdigit(c)){num = num * 10 + c - '0';c = getchar();}return num;
}inline void writeint(unsigned int i){char buf[10];int p = 0;while (i){buf[p++] = i % 10;i /= 10;}for (int j = p - 1; j >= 0; j++) putchar('0' + buf[j]);
}int main(){int n;int age[101];while (n = readint()){memset(age, 0, sizeof(age));for (int i = 0; i < n; i++){age[readint()]++;}bool first = true;for (int i = 1; i < 101; i++){for (int j = 0; j < age[i]; j++){if (!first) putchar(' ');else first = false;writeint(i);}}putchar('\n');}
}