Persistent Segment Tree example

Author: coderick14

persistent_segtree.cpp

@@ -0,0 +1,225 @@
+// persistent segment trees 
+// Codechef MAY17 Long Challenge
+// Problem Name: Gotham PD
+// Problem Code : GPD
+#include <bits/stdc++.h>
+#define ll long long
+#define ull unsigned long long
+#define vi vector<ll>
+#define pp pair<ll,ll>
+#define mp make_pair
+#define PI acos(-1.0)
+#define all(v) v.begin(),v.end()
+#define pb push_back
+#define FOR(i,a,b) for(i=a;i<b;i++)
+#define FREV(i,a,b) for(i=a;i>=b;i--)
+#define INF 1e18
+
+#ifndef ONLINE_JUDGE
+#define gc getchar
+#define pc putchar
+#else
+#define gc getchar_unlocked
+#define pc putchar_unlocked
+#endif
+
+using namespace std;
+
+int read_int() {
+    char c = gc();
+    while((c < '0' || c > '9') && c != '-') c = gc();
+    int ret = 0, neg = 0;
+    if (c == '-') neg = 1, c = gc();
+    while(c >= '0' && c <= '9') {
+        ret = 10 * ret + c - 48;
+        c = gc();
+    }
+    return neg ? -ret : ret;
+}
+
+ll read_ll() {
+    char c = gc();
+    while((c < '0' || c > '9') && c != '-') c = gc();
+    ll ret = 0;
+    int neg = 0;
+    if (c == '-') neg = 1, c = gc();
+    while(c >= '0' && c <= '9') {
+        ret = 10 * ret + c - 48;
+        c = gc();
+    }
+    return neg ? -ret : ret;
+}
+
+struct node {
+    node* left;
+    node* right;
+
+    node() {
+        this->left = NULL;
+        this->right = NULL;
+    }
+};
+
+vi parent(300005);
+string bit_string;
+vector<node*> tree_roots;
+map<ll,ll> get_index_from_id;
+
+void create_tree(node* &root, ll key, ll parent_index) {
+    node* temp = root;
+    bit_string = bitset<32>(key).to_string();
+    int i;
+    if (parent_index == -1) {   
+        FOR(i,0,32) {
+            if (bit_string[i] == '0') {
+                root->left = new node();
+                root = root->left;
+            }
+            else {
+                root->right = new node();
+                root = root->right;
+            }
+        }
+    }
+    else {
+        node* parent_root = tree_roots[parent_index];
+        FOR(i,0,32) {
+            if (bit_string[i] == '0') {
+                root->left = new node();
+                if (parent_root != NULL) {
+                    root->right = parent_root->right;
+                    parent_root = parent_root->left;
+                }
+                root = root->left;
+
+            }
+            else {
+                root->right = new node();
+                if (parent_root != NULL) {
+                    root->left = parent_root->left;
+                    parent_root = parent_root->right;
+                }
+                root = root->right;
+            }
+        }
+    }
+    root = temp;
+}
+
+void solve(ll v, ll k, ll &min_answer, ll &max_answer) {
+    bit_string = bitset<32>(k).to_string();
+    node* root = tree_roots[v];
+    ll minim = 0, maxim = 0;
+    int i;
+
+    // find max
+    FREV(i,31,0) {
+        if (bit_string[31-i] == '0') {
+            if (root->right != NULL) {
+                maxim += (1<<i);
+                root = root->right;
+            }
+            else {
+                root = root->left;
+            }
+        }
+        else {
+            if (root->left != NULL) {
+                maxim += (1<<i);
+                root = root->left;
+            }
+            else {
+                root = root->right;
+            }
+        }
+    }
+
+    root = tree_roots[v];
+
+    // find min
+    FREV(i,31,0) {
+        if (bit_string[31-i] == '0') {
+            if (root->left != NULL) {
+                root = root->left;
+            }
+            else {
+                minim += (1<<i);
+                root = root->right;
+            }
+        }
+        else {
+            if (root->right != NULL) {
+                root = root->right;
+            }
+            else {
+                minim += (1<<i);
+                root = root->left;
+            }
+        }
+    }
+
+    min_answer = minim;
+    max_answer = maxim;
+}
+
+int main() {
+	ll i,u,v,r,r_key,k,q,n,min_answer,max_answer,index=0;
+    int t;
+    n = read_ll();
+    q = read_ll();
+    r = read_ll();
+    r_key = read_ll();
+    tree_roots.pb(new node());
+    get_index_from_id[r] = index;
+    parent[index] = -1;
+    create_tree(tree_roots[index], r_key, -1);
+    index++;
+    FOR(i,0,n-1) {
+        u = read_ll();
+        v = read_ll();
+        k = read_ll();
+
+        tree_roots.pb(new node());
+
+        get_index_from_id[u] = index;
+        parent[index] = get_index_from_id[v];
+        create_tree(tree_roots[index], k, parent[index]);
+        index++;
+    }
+
+    ll last_answer = 0;
+    FOR(i,0,q) {
+        t = read_int();
+        t ^= last_answer;
+
+        if(t == 0) {
+            v = read_ll();
+            u = read_ll();
+            k = read_ll();
+
+            u ^= last_answer;
+            v ^= last_answer;
+            k ^= last_answer;
+
+            tree_roots.pb(new node());
+
+            get_index_from_id[u] = index;
+            parent[index] = get_index_from_id[v];
+            create_tree(tree_roots[index], k, parent[index]);;
+            index++;
+        }
+        else {
+            v = read_ll();
+            k = read_ll();
+
+            v ^= last_answer;
+            k ^= last_answer;
+
+            solve(get_index_from_id[v],k,min_answer,max_answer);
+            printf("%lld %lld\n", min_answer, max_answer);
+
+            last_answer = min_answer^max_answer;
+        }
+    }
+	return 0;
+}