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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,66 @@ | ||
| import sys | ||
| from heapq import * | ||
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| def input(): return sys.stdin.readline().rstrip() | ||
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| N, P, K = map(int, input().split()) | ||
| graph = [[int(1e9) for _ in range(N+1)] for _ in range(N+1)] | ||
|
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| for _ in range(P): | ||
| start, destination, cost = map(int, input().split()) | ||
| graph[start][destination] = min(graph[start][destination], cost) | ||
| graph[destination][start] = min(graph[destination][start], cost) | ||
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| def check(mid): | ||
| if dijkstra(mid): return True | ||
| return False | ||
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| def dijkstra(_max): | ||
| visited = set() | ||
| DP = [[int(1e9) for _ in range(K+1)] for _ in range(N+1)] | ||
| DP[1][K] = 0 | ||
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| # ๊ฐ์ ์ฝ์คํธ, ๋จ์ ๊ธฐํ, ํ์ฌ ๋ ธ๋ | ||
| heap = [(0, K, 1)] | ||
| while heap: | ||
| now_cost, now_remain, now_node = heappop(heap) | ||
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| if (now_node, now_remain) in visited: continue | ||
| visited.add((now_node, now_remain)) | ||
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| if DP[now_node][now_remain] < now_cost: continue | ||
| DP[now_node][now_remain] = now_cost | ||
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| if now_node == N: | ||
| return True | ||
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| for idx, cost in enumerate(graph[now_node]): | ||
| if idx == 0: continue | ||
| if cost == int(1e9): continue | ||
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| if cost <= _max: | ||
| if (idx, now_remain) in visited: continue | ||
| if DP[idx][now_remain] > cost: heappush(heap, (cost, now_remain, idx)) | ||
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| elif cost > _max and now_remain >= 1: | ||
| if (idx, now_remain-1) in visited: continue | ||
| if DP[idx][now_remain-1] > cost: heappush(heap, (cost, now_remain-1, idx)) | ||
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| for idx in range(1, K+1): | ||
| if DP[N][idx] != int(1e9): return True | ||
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| return False | ||
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| answer = int(1e9) | ||
| left = -1 | ||
| right = 1_000_001 | ||
| while left+1<right: | ||
| mid = (left + right) // 2 | ||
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| if check(mid): | ||
| right = mid | ||
| answer = mid | ||
| else: left = mid | ||
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| if answer != int(1e9): print(answer) | ||
| else: print(-1) |