teamnote history merge

2025spring/source/DP/LIS.cpp

@@ -0,0 +1,17 @@
+template<class I> vi lis(const vector<I>& S) {
+	if (S.empty()) return {};
+	vi prev(sz(S));
+	typedef pair<I, int> p;
+	vector<p> res;
+	rep(i,0,sz(S)) {
+		// change 0 -> i for longest non-decreasing subsequence
+		auto it = lower_bound(all(res), p{S[i], 0});
+		if (it == res.end()) res.emplace_back(), it = res.end()-1;
+		*it = {S[i], i};
+		prev[i] = it == res.begin() ? 0 : (it-1)->second;
+	}
+	int L = sz(res), cur = res.back().second;
+	vi ans(L);
+	while (L--) ans[L] = cur, cur = prev[cur];
+	return ans;
+}