Submission #719177

#	Time	Username	Problem	Language	Result	Execution time	Memory
719177		thimote75	Mutating DNA (IOI21_dna)	C++17	100 / 100	75 ms	16620 KiB

dna

#include "dna.h"

#include <bits/stdc++.h>
using namespace std;

int to_int(char ch) {
	if (ch == 'A') return 0;
	if (ch == 'C') return 1;
	if (ch == 'T') return 2;

	assert(false);
}

struct SGD {
	int m[3][3];

	void init () {
		for (int i = 0; i < 3; i ++)
			for (int j = 0; j < 3; j ++)
				m[i][j] = 0;
	}
	SGD () { init(); }
	SGD (char a, char b) {
		init();
		int ia = to_int(a);
		int ib = to_int(b);

		m[ia][ib] ++;
	}

	SGD merge (SGD &other) {
		SGD res;

		for (int i = 0; i < 3; i ++)
			for (int j = 0; j < 3; j ++)
				res.m[i][j] = m[i][j] + other.m[i][j];
	
		return res;
	}
	int flux (int i) {
		int f = 0;
		for (int j = 0; j < 3; j ++) {
			if (j == i) continue ;

			f -= m[i][j];
			f += m[j][i];
		}

		return f;
	}
	int distance () {
		if (flux(0) != 0
		 || flux(1) != 0
		 || flux(2) != 0)
		 	return -1;

		int r[3][3];
		for (int i = 0; i < 3; i ++) for (int j = 0; j < 3; j ++)
			r[i][j] = m[i][j];
		
		int dist = 0;
		for (int i = 0; i < 3; i ++) {
			for (int j = i + 1; j < 3; j ++) {
				dist += min(r[j][i], r[i][j]);

				r[i][j] -= r[j][i];
				r[j][i]  = 0;
			}
		}

		int residual  = abs(r[0][2]);
		if (residual != abs(r[0][1])) return -1;
		if (residual != abs(r[1][2])) return -1;

		dist += 2 * residual;

		return dist;
	}
};

struct SegTree {
	int size, start, height;
	vector<SGD> tree;

	SegTree () = default;
	SegTree (vector<SGD> &values) {
		size = values.size();
		height = ceil(log2(size));
		start = 1 << height;

		tree.resize(start << 1);

		for (int i = 0; i < size; i ++)
			tree[i + start] = values[i];
	
		for (int i = start - 1; i >= 1; i --) {
			int n0 = i << 1;
			int n1 = n0 + 1;

			tree[i] = tree[n0].merge(tree[n1]);
		}
	}

	SGD query (int x, int y) {
		x += start;
		y += start;

		SGD res;

		while (x < y) {
			if ((x & 1) == 1) res = res.merge(tree[x]);
			if ((y & 1) == 0) res = res.merge(tree[y]);
		
			x = (x + 1) >> 1;
			y = (y - 1) >> 1;
		}

		if (x == y) res = res.merge(tree[x]);

		return res;
	}
};

vector<SGD> object_array;
SegTree tree;

void init(string a, string b) {
	object_array.resize(a.size());
	for (int i = 0; i < a.size(); i ++)
		object_array[i] = SGD(a[i], b[i]);

	tree = SegTree(object_array);
}

int get_distance(int x, int y) {
	SGD res = tree.query(x, y);

	return res.distance();
}

Compilation message (stderr)

dna.cpp: In function 'void init(std::string, std::string)':
dna.cpp:129:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |  for (int i = 0; i < a.size(); i ++)
      |                  ~~^~~~~~~~~~

• Subtask 1: 21 / 21
• Subtask 2: 22 / 22
• Subtask 3: 13 / 13
• Subtask 4: 28 / 28
• Subtask 5: 16 / 16