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| class Solution {
public boolean findWhetherExistsPath(int n, int[][] graph, int start, int target) {
List<Set<Integer>> startToTargetSetList = new ArrayList<>(n);
for (int i = 0; i < n; i++) {
startToTargetSetList.add(new HashSet<>());
}
for (int[] edge : graph) {
startToTargetSetList.get(edge[0]).add(edge[1]);
}
return dfs(startToTargetSetList, start, target);
}
private boolean dfs(List<Set<Integer>> startToTargetSetList, int start, int target) {
Set<Integer> targetSet = startToTargetSetList.get(start);
if (targetSet.contains(target)) {
return true;
} else {
for (Integer candidate : targetSet) {
if (dfs(startToTargetSetList, candidate, target)) {
return true;
}
}
return false;
}
}
}
|