teamnote history merge

2026-06-03 09:36:52 +09:00
parent f50ed902fe
commit 7176febe54
142 changed files with 13243 additions and 0 deletions
--- a/2025fall/source/String/Eertree.cpp
+++ b/2025fall/source/String/Eertree.cpp
@@ -0,0 +1,38 @@
+struct Eertree {
+    int len[N], link[N], nxt[N][26], r[N];
+    long long cnt[N]; int sz, last, n;
+    char s[N];
+    Eertree() {
+        memset(nxt, 0, sizeof(nxt));
+        memset(cnt, 0, sizeof(cnt));
+        s[0] = -1;
+        n = 0; sz = 2; last = 1;
+        len[0] = -1; link[0] = 0;
+        len[1] = 0; link[1] = 0;
+    }
+    int get_link(int v) {
+        while (s[n-len[v]-1] != s[n]) v = link[v];
+        return v;
+    }
+    void insert(char c) {
+        s[++n] = c;
+        int cur = get_link(last);
+        if (!nxt[cur][c-'a']) {
+            int now = sz++;
+            r[now] = n;
+            len[now] = len[cur] + 2;
+            if (len[now] == 1) link[now] = 1;
+            else link[now] = nxt[get_link(link[cur])][c-'a'];
+            nxt[cur][c-'a'] = now;
+        }
+        last = nxt[cur][c-'a'];
+        cnt[last]++;
+    }
+    void propagate() { fore(i, sz-1, 2) cnt[link[i]] += cnt[i]; }
+};
+
+Eertree et; forr(i, n) et.insert(s[i]);
+int m = et.sz; et.propagate();
+fors(i, 2, m-1) ans = max(ans, et.cnt[i] * et.len[i]);
+// node i : s[(et.r[i]-et.len[i]+1)~(et.r[i])]
+// distinct count of pal : m-2; count of node i : et.cnt[i];