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// 1697. Checking Existence of Edge Length Limited Paths
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
/*
* an undirected graph of 'n' nodes is defined by 'edge_list',
* where 'edge_list[i] = [ui, vi, disi]' denotes an edge between
* nodes 'ui' and 'vi' with distance 'disi'. note that there may
* be multiple edges between two nodes. given an array 'queries',
* where 'queries[j] = [pj, qj, limitj]', your task is to determine
* for each 'queries[j]' whthere there is a path between 'pj' and
* 'qj' such that each edge on the path has a distance strictly less
* than 'limitj'. return boolean array where 'ans.length == queries.len'
* and the j'th value of 'ans' is true if there is a path for
* 'queries[j]' is true, and false otherwise
*/
int *root, **qcopy;
int find(int x) {
if (x == root[x])
return x;
else
return root[x] = find(root[x]);
}
int cmp(void const *a, void const *b) {
return (*(int **)a)[2] - (*(int **)b)[2];
}
int cmp2(void const *a, void const *b) {
return qcopy[*(int *)a][2] - qcopy[*(int *)b][2];
}
bool *distanceLimitedPathsExist(int n, int **edge_list, int edge_list_size,
int *edge_list_col_size, int **queries,
int queries_size, int *queries_col_size,
int *return_size) {
*return_size = queries_size;
int i = 0;
root = (int *)malloc(sizeof(int) * n);
for (i = 0; i < n; i++)
root[i] = i;
bool *ans = (bool *)malloc(sizeof(bool) * queries_size);
int idx[queries_size];
for (i = 0; i < queries_size; ++i)
idx[i] = i;
qcopy = queries;
qsort(idx, queries_size, sizeof(int), cmp2);
qsort(edge_list, edge_list_size, sizeof(int *), cmp);
int j = 0;
for (i = 0; i < queries_size; ++i) {
int curr = idx[i], len = queries[curr][2];
while (j < edge_list_size && edge_list[j][2] < len) {
int a = find(edge_list[j][0]), b = find(edge_list[j][1]);
root[b] = a;
j++;
}
if (find(queries[curr][0]) == find(queries[curr][1]))
ans[curr] = 1;
else
ans[curr] = 0;
}
return ans;
}
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