DP-Algo

Algorithm/DP-DynamicProgramming/Tree-DP/树的最大独立集.cpp

@@ -0,0 +1,50 @@
+#include <iostream>
+#include <utility>
+#include <vector>
+using namespace std;
+void dfs(vector<vector<int>>& d, const vector<vector<int>>& adj_, vector<bool>& vs, int v){
+	d[v][0] = 0;
+	d[v][1] = 1;
+	for(auto x : adj_[v]){
+		if(vs[x] == false) {
+			vs[x] = true;
+			dfs(d, adj_, vs, x);
+			//<2F><><EFBFBD><EFBFBD>
+			d[v][0] += max(d[x][0], d[x][1]);  // <20><>ѡu<D1A1><75><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѡ
+        	d[v][1] += d[x][0];  // ѡu<D1A1><75><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>벻ѡ<EBB2BB><D1A1> 
+		}
+		
+	}
+} 
+
+
+int main(){
+	//ͼ<>Ļ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD>vector<6F><72><EFBFBD>ڽӱ<DABD><D3B1><EFBFBD><EFBFBD><EFBFBD> 
+	int n;
+	cin >> n;
+	vector<vector<int>> adj(n);
+	vector<vector<int>> dp(n, vector<int>(2, 0));
+	vector<bool> visited(n, false);
+	//vector<vector<int>> choose(n, vector<int>(n, 0));
+	//<2F><><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD>0<EFBFBD><30>ʼ<EFBFBD><CABC>n - 1 
+	for(int i = 0; i < n - 1; i++){
+		int a, b;
+		cin >> a >> b;
+		adj[a].push_back(b);
+		adj[b].push_back(a);
+	}
+	/*
+	for(int l = 2; l <= n; l++){
+		for(int i = 0; i < n - l + 1; i++){
+			int j = i + l - 1;
+			for(int k = i; k < j; k++){
+				if(adj[i][j])
+				d[i][j] = max(dp[i][j], )
+			}
+		}
+	}*/
+	visited[0] = true;
+	dfs(dp, adj, visited, 0);  // <20><>0Ϊ<30><CEAA>
+    cout << max(dp[0][0], dp[0][1]) << endl;
+	return 0;
+}

Algorithm/DP-DynamicProgramming/Tree-DP/树的直径-最远点对.cpp

@@ -0,0 +1,60 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+using namespace std;
+vector<vector<int>> adj;
+vector<int> dp;
+void dfs(int v, int parent){
+	//no return;
+	for(auto x : adj[v]){
+		if(x == parent) continue;
+		dfs(x, v);
+		dp[v] = max(dp[v], dp[x] + 1);
+	}
+}
+
+int main(){
+	int n;
+	cin >> n;
+	adj.resize(n, vector<int>());
+	dp.resize(n, 1);
+	vector<bool> visited(n, false);
+	//<2F><><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD>0<EFBFBD><30>ʼ<EFBFBD><CABC>n - 1 
+	for(int i = 0; i < n - 1; i++){
+		int a, b;
+		cin >> a >> b;
+		adj[a].push_back(b);
+		adj[b].push_back(a);
+	}
+	dfs(0, -1);
+	int mmax = 0;
+	if(adj[0].size() == 1) cout << dp[0] << endl;
+	else{
+		vector<int> tmp;
+		for(auto x : adj[0]){
+			tmp.push_back(dp[x]);
+		}
+		sort(tmp.begin(), tmp.end());
+		mmax = *(tmp.end() - 1) + *(tmp.end() - 2);
+		cout << mmax + 1<< endl;
+	}
+	return 0;
+}
+/*
+7
+0 1
+0 2
+1 3
+1 4
+2 5
+2 6
+
+8
+0 1
+0 2
+1 3
+1 4
+2 5
+2 6
+3 7
+*/