Merge pull request #248 from H4wk-3yE/patch-4

Create string_query.cpp

Author: probot-auto-merge[bot]

fenwick_tree/string_query.cpp

@@ -0,0 +1,106 @@
+// https://www.hackerearth.com/practice/data-structures/advanced-data-structures/fenwick-binary-indexed-trees/practice-problems/algorithm/string-query-22/
+
+/*
+				C++
+				encoding: UTF-8
+				Modified: <04/Oct/2019 02:37:20 PM>
+
+				✪ H4WK3yE乡
+				Mohd. Farhan Tahir
+				Indian Institute Of Information Technology (IIIT), Gwalior
+*/
+
+#include <bits/stdc++.h>
+#ifdef LOCAL_PROJECT
+#	include <prettypr.hpp>
+#endif
+
+using namespace std;
+
+// clang-format off
+
+#define         ll                     long long
+#define         ve                     vector
+#define         pb                     push_back
+#define         endl                   "\n"
+#define         ff                     first
+#define         ss                     second
+#define         pii                    pair<int, int>
+#define         len(v)                 int(v.size())
+#define         all(v)                 v.begin(), v.end()
+#define         reset(a, b)            memset(a, b, sizeof(a));
+#define         fr(i, s, n)            for (int i = s ; i < n ; ++i)
+#define         dfr(i, s, n)           for (int i = s ; i > n ; --i)
+
+template < typename T > void pr (const T& t) {
+    cout << t << "\n";
+}
+
+template < typename T, typename U, typename... ARGS >
+void pr (const T& t, const U& u, const ARGS&... args) {
+    cout << t << " ";
+    pr (u, args...);
+}
+
+// clang-format on
+
+const int N = 2e5 + 5;
+int arr[N], bit[N][26];
+string s;
+int n;
+
+void update (int i, int c, int val) {
+	while (i <= n) {
+		bit[i][c] += val;
+		i += (i & (-i));
+	}
+}
+
+int query (int i, int x) {
+	int ans = 0;
+	while (i > 0) {
+		ans += bit[i][x];
+		i -= (i & (-i));
+	}
+	return ans;
+}
+
+int search (int k, int x) {
+	int low = 1, high = n;
+	while (low <= high) {
+		int mid = (low + high + 1) >> 1;
+		if (query (mid, x) < k) {
+			low = mid + 1;
+		} else {
+			high = mid - 1;
+		}
+	}
+	return low;
+}
+
+signed main () {
+	ios_base::sync_with_stdio (false), cin.tie (nullptr);
+	cin >> s;
+	n = len (s);
+	fr (i, 0, n) {
+		update (i + 1, s[i] - 'a', 1);
+	}
+
+	int tc;
+	cin >> tc;
+	while (tc--) {
+		int k;
+		char x;
+		cin >> k >> x;
+		int idx = search (k, x - 'a');
+		update (idx, x - 'a', -1);
+		s[idx - 1] = '#';
+	}
+
+	for (auto i : s) {
+		if (i != '#') cout << i;
+	}
+	cout << "\n";
+
+	return 0;
+}