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cs: add «2976. Minimum Cost to Convert String I»

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Signed-off-by: Matej Focko <me@mfocko.xyz>
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Matej Focko 2024-07-27 20:12:49 +02:00
parent 38a46aeb26
commit 2a8ffbe9d7
Signed by: mfocko
GPG key ID: 7C47D46246790496
1 changed files with 56 additions and 0 deletions
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public class Solution {
private readonly int UNREACHABLE = 1_000_000_007;
private readonly int LETTERS = 26;
private void FloydWarshall(int n, int[,] distances) {
for (int k = 0; k < n; ++k) {
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
distances[i, j] = Math.Min(
distances[i, j],
distances[i, k] + distances[k, j]
);
}
}
}
}
private int[,] ConstructGraph(char[] original, char[] changed, int[] costs) {
var distances = new int[LETTERS, LETTERS];
// Everything's unreachable
for (var i = LETTERS * LETTERS - 1; i >= 0; --i) {
distances[i / LETTERS, i % LETTERS] = UNREACHABLE;
}
// Go through the possible changes
for (var i = 0; i < original.length; ++i) {
var (u, v, cost) = (original[i] - 'a', changed[i] - 'a', costs[i]);
distances[u, v] = Math.Min(distances[u, v], cost);
}
// Handle self-loops
for (var i = 0; i < LETTERS; ++i) {
distances[i, i] = 0;
}
return distances;
}
public long MinimumCost(string source, string target, char[] original, char[] changed, int[] cost) {
var graph = ConstructGraph(original, changed, cost);
FloydWarshall(LETTERS, graph);
var minCost = 0;
for (int i = 0; i < source.Length; ++i) {
var operationCost = graph[source[i] - 'a', target[i] - 'a'];
if (operationCost == UNREACHABLE) {
return -1;
}
minCost += operationCost;
}
return minCost;
}
}