题意:问一些7位数(可能有前导0,可到达100000个)是否有重复,将重复的按字典序从小到大输出并输出重复次数,没有的话输出“No duplicates.”。
题目链接:http://poj.org/problem?id=1002
——>>本来题目很水的,在刷后缀数组,中间有个基数排序的东西,于是用基数排序来做这题。。。
#include <cstdio>
#include <cstring>
#include <cctype>using namespace std;const int maxn = 100000 + 10;int n, p[maxn][8], figure[maxn];
int c[15], sa[maxn], fa[maxn]; //sa[i]表示现在的第i位是原来的第sa[i]位
int G[] = {2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 0, 7, 7, 8, 8, 8, 9, 9, 9, 0};void read() {for(int i = 0; i < n; i++) {int bit = 0;while(bit < 7) {char ch = getchar();if(ch == '\n') break;if(ch != '-' && ch != 'Q' && ch != 'Z') {if(isdigit(ch)) p[i][bit++] = ch - '0';else p[i][bit++] = G[ch-'A'];}}if(bit == 7) while(getchar() != '\n');}
}void radixsort(){for(int i = 0; i < n; i++) fa[i] = i; //初始化for(int bit = 6; bit >= 0; bit--) { //第bit位memset(c, 0, sizeof(c));for(int i = 0; i < n; i++) c[p[i][bit]]++; //数字出现的次数for(int i = 1; i <= 9; i++) c[i] += c[i-1]; //该数字最后一次出现应排在的位置for(int i = n-1; i >= 0; i--) sa[--c[p[fa[i]][bit]]] = fa[i];for(int i = 0; i < n; i++) fa[i] = sa[i];}
}void solve() {radixsort(); //基数排序for(int i = 0; i < n; i++) { //求十进制数figure[i] = 0;for(int j = 0; j < 7; j++) figure[i] = figure[i] * 10 + p[i][j];}bool ok = 0; //是否有重复for(int i = 1; i < n; i++) if(figure[sa[i]] == figure[sa[i-1]]) {int cnt = 2;while(i+1 < n && figure[sa[i+1]] == figure[sa[i]]) {cnt++;i++;}for(int j = 0; j < 3; j++) printf("%d", p[sa[i]][j]);printf("-");for(int j = 3; j < 7; j++) printf("%d", p[sa[i]][j]);printf(" %d\n", cnt);ok = 1;}if(!ok) puts("No duplicates.");
}int main()
{while(scanf("%d ", &n) == 1) {read();solve();}return 0;
}