1 files changed, 46 insertions, 0 deletions
diff --git a/content/datastructures/lichao.cpp b/content/datastructures/lichao.cpp
new file mode 100644
index 0000000..f66778e
--- /dev/null
+++ b/content/datastructures/lichao.cpp
@@ -0,0 +1,46 @@
+vector<ll> xs; // IMPORTANT: Initialize before constructing!
+int findX(int i) {return lower_bound(all(xs), i) - begin(xs);}
+
+struct Fun { // Default: Linear function. Change as needed. 
+	ll m, c;
+	ll operator()(int x) {return m*xs[x] + c;}
+};
+
+// Default: Computes min. Change lines with comment for max.
+struct Lichao {
+	static constexpr Fun id = {0, inf}; // {0, -inf}
+	int n, cap;
+	vector<Fun> seg;
+	Lichao() : n(sz(xs)), cap(2<<__lg(n)), seg(2*cap, id) {}
+	
+	void _insert(Fun f, int l, int r, int i) {
+		while (i < 2*cap){
+			int m = (l+r)/2;
+			if (m >= n) {r = m; i = 2*i; continue;}
+			Fun &g = seg[i];
+			if (f(m) < g(m)) swap(f, g); // >
+			if (f(l) < g(l)) r = m, i = 2*i; // >
+			else l = m, i = 2*i+1;
+	}}
+	void insert(Fun f) {_insert(f, 0, cap, 1);}
+
+	void _segmentInsert(Fun f, int l, int r, int a, int b, int i) {
+		if (l <= a && b <= r) _insert(f, a, b, i);
+		else if (a < r && l < b){
+			int m = (a+b)/2;
+			_segmentInsert(f, l, r, a, m, 2*i);
+			_segmentInsert(f, l, r, m, b, 2*i+1);
+	}}
+	void segmentInsert(Fun f, ll l, ll r) {
+		_segmentInsert(f, findX(l), findX(r), 0, cap, 1);
+	}
+
+	ll _query(int x) {
+		ll ans = inf; // -inf
+		for (int i = x + cap; i > 0; i /= 2) {
+			ans = min(ans, seg[i](x)); // max
+		}
+		return ans;
+	}
+	ll query(ll x) {return _query(findX(x));}
+};