1353

src/1353.c

@@ -0,0 +1,91 @@
+//
+// Created by gint on 2025/7/7.
+//
+#include <stdlib.h>
+
+int cmpEvent(const void *a, const void *b)
+{
+    int *eventA = *(int **)a;
+    int *eventB = *(int **)b;
+    return eventA[0] - eventB[0];
+}
+
+int compare(const void *a, const void *b)
+{
+    return *(int *)a - *(int *)b;
+}
+
+// 简易小根堆操作
+void push(int *heap, int *size, int val)
+{
+    int i = (*size)++;
+    heap[i] = val;
+    while (i > 0 && heap[(i - 1) / 2] > heap[i])
+    {
+        int tmp = heap[i];
+        heap[i] = heap[(i - 1) / 2];
+        heap[(i - 1) / 2] = tmp;
+        i = (i - 1) / 2;
+    }
+}
+
+int pop(int *heap, int *size)
+{
+    int result = heap[0];
+    heap[0] = heap[--(*size)];
+    int i = 0;
+    while (i * 2 + 1 < *size)
+    {
+        int j = i * 2 + 1;
+        if (j + 1 < *size && heap[j + 1] < heap[j])
+            j++;
+        if (heap[i] <= heap[j])
+            break;
+        int tmp = heap[i];
+        heap[i] = heap[j];
+        heap[j] = tmp;
+        i = j;
+    }
+    return result;
+}
+
+int maxEvents(int **events, int eventsSize, int *eventsColSize)
+{
+    qsort(events, eventsSize, sizeof(int *), cmpEvent);
+
+    int minDay = events[0][0], maxDay = 0;
+    for (int i = 0; i < eventsSize; i++)
+    {
+        if (events[i][1] > maxDay)
+            maxDay = events[i][1];
+    }
+
+    int heap[eventsSize];
+    int heapSize = 0;
+
+    int day = minDay, idx = 0, res = 0;
+
+    for (day = minDay; day <= maxDay; day++)
+    {
+        // 把今天开始的会议加进堆
+        while (idx < eventsSize && events[idx][0] == day)
+        {
+            push(heap, &heapSize, events[idx][1]);
+            idx++;
+        }
+
+        // 去掉已过期的会议
+        while (heapSize > 0 && heap[0] < day)
+        {
+            pop(heap, &heapSize);
+        }
+
+        // 选择今天可以开的最早结束的会议
+        if (heapSize > 0)
+        {
+            pop(heap, &heapSize);
+            res++;
+        }
+    }
+    return res;
+}