每个字符串至少出现两次且不重复的最长子串
题目链接：https://cn.vjudge.net/contest/318888#problem/L
思路：
1 #include <stdio.h> 2 #include <iostream> 3 #include <algorithm> 4 #include <string.h> 5 #include <stdlib.h> 6 #include <math.h> 7 #include <queue> 8 #include <set> 9 10 #define INF 0x3f3f3f3f 11 #define pii pair<int,int> 12 #define LL long long 13 using namespace std; 14 typedef unsigned long long ull; 15 const int MAXN = 2e5 + 10; 16 int t; 17 int wa[MAXN], wb[MAXN], wv[MAXN], ws_[MAXN]; 18 void Suffix(int *r, int *sa, int n, int m) 19 { 20 int i, j, k, *x = wa, *y = wb, *t; 21 for(i = 0; i < m; ++i) ws_[i] = 0; 22 for(i = 0; i < n; ++i) ws_[x[i] = r[i]]++; 23 for(i = 1; i < m; ++i) ws_[i] += ws_[i - 1]; 24 for(i = n - 1; i >= 0; --i) sa[--ws_[x[i]]] = i; 25 for(j = 1, k = 1; k < n; j *= 2, m = k) 26 { 27 for(k = 0, i = n - j; i < n; ++i) y[k++] = i; 28 for(i = 0; i < n; ++i) if(sa[i] >= j) y[k++] = sa[i] - j; 29 for(i = 0; i < n; ++i) wv[i] = x[y[i]]; 30 for(i = 0; i < m; ++i) ws_[i] = 0; 31 for(i = 0; i < n; ++i) ws_[wv[i]]++; 32 for(i = 1; i < m; ++i) ws_[i] += ws_[i - 1]; 33 for(i = n - 1; i >= 0; --i) sa[--ws_[wv[i]]] = y[i]; 34 t = x; 35 x = y; 36 y = t; 37 for(x[sa[0]] = 0, i = k = 1; i < n; ++i) 38 x[sa[i]] = (y[sa[i - 1]] == y[sa[i]] && y[sa[i - 1] + j] == y[sa[i] + j]) ? k - 1 : k++; 39 } 40 } 41 int Rank[MAXN], height[MAXN], sa[MAXN], r[MAXN]; 42 char s[MAXN]; 43 int indexx[MAXN],vis[MAXN]; 44 void calheight(int *r,int *sa,int n) 45 { 46 int i,j,k=0; 47 for(i=1; i<=n; i++)Rank[sa[i]]=i; 48 for(i=0; i<n; height[Rank[i++]]=k) 49 for(k?k--:0,j=sa[Rank[i]-1]; r[i+k]==r[j+k]; k++); 50 } 51 52 struct Node{ 53 int cnt,maxsa,minsa; 54 void init(){ 55 cnt = 0; 56 maxsa = -1; 57 minsa = MAXN; 58 } 59 }node[20]; 60 61 bool check(int x,int n){ 62 int tot = 0; 63 int idx,lidx; 64 for (int i=0;i<t;i++){ 65 node[i].init(); 66 } 67 memset(vis,0, sizeof(vis)); 68 for (int i=1;i<n;i++){ 69 idx = indexx[sa[i]],lidx = indexx[sa[i-1]]; 70 if (i == n-1){ 71 for (int k=0;k<t;k++){ 72 if (node[k].cnt>=2 && node[k].maxsa-node[k].minsa>=x){ 73 tot++; 74 } 75 node[k].init(); 76 } 77 if (tot == t){ 78 return true; 79 } 80 tot = 0; 81 break; 82 } 83 if (height[i]>=x){ 84 if (!vis[i]){ 85 vis[i] = 1; 86 node[idx].cnt++; 87 node[idx].maxsa = max(sa[i],node[idx].maxsa); 88 node[idx].minsa = min(sa[i],node[idx].minsa); 89 } 90 if (!vis[i-1]){ 91 vis[i-1] = 1; 92 node[lidx].cnt++; 93 node[lidx].maxsa = max(sa[i-1],node[lidx].maxsa); 94 node[lidx].minsa = min(sa[i-1],node[lidx].minsa); 95 } 96 } 97 else{ 98 for (int k=0;k<t;k++){ 99 if (node[k].cnt>=2 && node[k].maxsa-node[k].minsa>=x){ 100 tot++; 101 } 102 node[k].init(); 103 } 104 if (tot == t){ 105 return true; 106 } 107 tot = 0; 108 } 109 } 110 return false; 111 } 112 113 114 int main() 115 { 116 int T; 117 scanf("%d",&T); 118 while (T--) { 119 scanf("%d",&t); 120 int XX = 30; 121 int n = 0; 122 for (int i=0;i<t;i++){ 123 scanf("%s",s); 124 int len = strlen(s); 125 for (int j=0;j<len;j++){ 126 r[n++] = s[j]-'a'+1; 127 indexx[n-1] = i; 128 } 129 indexx[n] = i; 130 r[n++] = XX++; 131 } 132 r[n] = 0; 133 Suffix(r,sa,n+1,128); 134 calheight(r,sa,n); 135 int L=1,R=10000,mid,len=0; 136 while (L<=R){ 137 mid = (L+R)>>1; 138 if (check(mid,n)){ 139 len = mid; 140 L = mid+1; 141 }else 142 R = mid-1; 143 } 144 printf("%d\n",len); 145 } 146 return 0; 147 }
