题意:给出2个字符串 求最短的连续的公共字符串 并且该字符串在原串中只出现一次
思路:把2个字符串合并起来求height 后缀数组height的应用
#include <cstdio> #include <cstring> #include <algorithm> using namespace std; const int maxn = 100010; char s[maxn]; int sa[maxn]; int t[maxn], t2[maxn], c[maxn]; int rank[maxn], height[maxn]; int l1, l2; void build_sa(int m, int n) { int i, *x = t, *y = t2; for(i = 0; i < m; i++) c[i] = 0; for(i = 0; i < n; i++) c[x[i] = s[i]]++; for(i = 1; i < m; i++) c[i] += c[i-1]; for(i = n-1; i >= 0; i--) sa[--c[x[i]]] = i; for(int k = 1; k <= n; k <<= 1) { int p = 0; for(i = n-k; i < n; i++) y[p++] = i; for(i = 0; i < n; i++) if(sa[i] >= k) y[p++] = sa[i] - k; for(i = 0; i < m; i++) c[i] = 0; for(i = 0; i < n; i++) c[x[y[i]]]++; for(i = 0; i < m; i++) c[i]+= c[i-1]; for(i = n-1; i >= 0; i--) sa[--c[x[y[i]]]] = y[i]; swap(x,y); p = 1; x[sa[0]] = 0; for(i = 1; i < n; i++) x[sa[i]] = y[sa[i-1]] == y[sa[i]] && y[sa[i-1]+k] == y[sa[i]+k] ? p-1 : p++; if(p >= n) break; m = p; } } void getHeight(int n) { int k = 0; for(int i = 0; i <= n; i++) rank[sa[i]] = i; for(int i = 0; i < n; i++) { if(k) k--; int j = sa[rank[i]-1]; while(s[i+k] == s[j+k]) k++; height[rank[i]] = k; } } bool ok(int m, int n) { int cnt1 = 0, cnt2 = 0; for(int i = 1; i <= n; i++) { if(height[i] >= m) { if(sa[i-1] < l1) cnt1++; if(sa[i-1] > l1) cnt2++; } else { if(sa[i-1] < l1) cnt1++; if(sa[i-1] > l1) cnt2++; if(cnt1 == 1 && cnt2 == 1) return true; cnt1 = cnt2 = 0; } } return false; } int main() { char a[5555], b[5555]; while(scanf("%s %s", &a, &b) != EOF) { l1 = strlen(a); l2 = strlen(b); int n = 0; for(int i = 0; i < l1; i++) s[n++] = a[i]; s[n++] = ‘z‘+1; for(int i = 0; i < l2; i++) s[n++] = b[i]; s[n] = 0; build_sa(128, n+1); getHeight(n); int l = 1, r = 5000; int ans = -1; int len = min(l1, l2); for(int i = 1; i <= len; i++) if(ok(i, n)) { ans = i; break; } if(ans <= 0) printf("-1\n"); else printf("%d\n", ans); } return 0; }
CF 427D Match & Catch 求最短唯一连续LCS,布布扣,bubuko.com
CF 427D Match & Catch 求最短唯一连续LCS
原文:http://blog.csdn.net/u011686226/article/details/24937469