YoonYn9915 / 6월 4주차 / 3문제

YoonYn9915/dijkstra/2025-06-23-[백준]-#1504-특정한 최단 경로.py

@@ -0,0 +1,35 @@
+import sys
+import heapq
+
+input = sys.stdin.readline
+INF = float('inf')
+
+N, E = map(int, input().split())
+graph = [[] for _ in range(N + 1)]
+for _ in range(E):
+    a, b, c = map(int, input().split())
+    graph[a].append((b, c))
+    graph[b].append((a, c))
+v1, v2 = map(int, input().split())
+
+
+
+def dijkstra(start, end):
+    dist = [INF] * (N + 1)
+    dist[start] = 0
+    hq = [(0, start)]
+    while hq:
+        len, node = heapq.heappop(hq)
+        if len > dist[node]:
+            continue
+        for next_node, val in graph[node]:
+            if dist[next_node] > dist[node] + val:
+                dist[next_node] = dist[node] + val
+                heapq.heappush(hq, (dist[next_node], next_node))
+    return dist[end]
+
+
+path1 = dijkstra(1, v1) + dijkstra(v1, v2) + dijkstra(v2, N)
+path2 = dijkstra(1, v2) + dijkstra(v2, v1) + dijkstra(v1, N)
+
+print(-1) if path1 >= INF and path2 >= INF else print(min(path1, path2))

YoonYn9915/dijkstra/2025-06-28-[백준]-#1753-최단 경로.py

@@ -0,0 +1,41 @@
+import heapq
+import sys
+
+input = sys.stdin.readline
+
+V, E = map(int, input().split())
+start = int(input())
+graph = [[] for _ in range(V + 1)]
+
+for _ in range(E):
+    u, v, w = map(int, input().split())
+
+    graph[u].append((v, w))
+
+
+def dijkstra(start):
+    distances = [float("inf")] * (V + 1)
+    distances[start] = 0
+    q = []
+    heapq.heappush(q, (distances[start], start))
+
+    while q:
+        cnt_distance, node = heapq.heappop(q)
+
+        if distances[node] < cnt_distance:
+            continue
+
+        for adjacency_node, distance in graph[node]:
+            cal_distance = distances[node] + distance
+
+            if cal_distance < distances[adjacency_node]:
+                distances[adjacency_node] = cal_distance
+                heapq.heappush(q, (cal_distance, adjacency_node))
+
+    return distances
+
+
+result = dijkstra(start)
+
+for i in range(1, len(result)):
+    print("INF" if result[i] == float("inf") else result[i])

YoonYn9915/implementation/2025-06-28-[백준]-#15905-스텔라가 치킨을 선물했어요.py

@@ -0,0 +1,18 @@
+N = int(input())
+
+arr = []
+
+for _ in range(N):
+    q, p = list(map(int, input().split()))
+    arr.append([q, p])
+
+arr.sort(reverse=True)
+
+count = 0
+for i in range(5, len(arr)):
+    if arr[4][0] == arr[i][0]:
+        count += 1
+    else:
+        break
+
+print(count)