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1753_dijkstra.py
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1753_dijkstra.py
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import sys
import math
import heapq
input = sys.stdin.readline
INF = math.inf
n, m = map(int, input().strip().split())
start = int(input().strip())
graph = [[] for _ in range(n + 1)]
for _ in range(m):
this_node, next_node, weight = map(int, input().strip().split())
graph[this_node].append((weight, next_node))
dist = [INF] * (n + 1)
heap = []
def dijkstra(start):
dist[start] = 0
heapq.heappush(heap, (0, start))
while heap:
weight, now = heapq.heappop(heap)
if dist[now] < weight:
continue
else:
for w, next_node in graph[now]:
next_weight = weight + w
if next_weight < dist[next_node]:
dist[next_node] = next_weight
heapq.heappush(heap, (next_weight, next_node))
dijkstra(start)
for i in range(1, len(dist)):
print('INF' if math.isinf(dist[i]) else dist[i])
# n, m = map(int, input().strip().split())
# start = int(input().strip())
# arr = [[0] * (n + 1) for _ in range(n + 1)]
# for _ in range(m):
# a, b, c = map(int, input().strip().split())
# arr[a][b] = c
# def dijkstra(arr, start, n):
# distance = [math.inf] * (n + 1)
# distance[start] = 0
# for _ in range(n - 1):
# for i in range(1, n + 1):
# for j in range(1, n + 1):
# if j != start:
# if arr[i][j] != 0:
# distance[j] = min(distance[j], distance[i] + arr[i][j])
# for i in range(1, len(distance)):
# print('INF' if math.isinf(distance[i]) else distance[i])
# dijkstra(arr, start, n)