commit be8e5b114b7cb5eff6e49c5381db163e1aa66761
parent 9fc2b923adb618d53a0eadc275c2dd6f8c6b4c8f
Author: Jack Sangdahl <jack@pngu.org>
Date: Thu, 11 Dec 2025 18:16:42 -0700
3433. count mentions per user
Diffstat:
2 files changed, 186 insertions(+), 0 deletions(-)
diff --git a/count_mentions_per_user.c b/count_mentions_per_user.c
@@ -0,0 +1,115 @@
+// 3433. Count Mentions Per User
+#include "leetcode.h"
+
+/*
+ * you are given an integer 'numberOfUsers' representing the total number of
+ * users and an array 'events' of size 'n x 3'. each 'events[i]' can be either
+ * of the following types: message event indicates that a set of users was
+ * mentioned in a message at 'timestamp' offline even indicates that the user
+ * 'id_i' has become offline at 'timestamp_i' for 60 time units. the user will
+ * automatically be online again at time 'timestamp_i + 60'. return an array
+ * 'mentions' that represents the number of mentions the user with id 'i' has
+ * across all 'MESSAGE' events. all users are initially online, and if a user
+ * goes offline or comes back online, their status change is processed before
+ * handling any message event that occurs at the same timestamp
+ */
+
+int str_to_num(char *s) {
+ int n = 0;
+ for (int i = 0; i < strlen(s); i++) {
+ n *= 10;
+ n += (int)(s[i] - '0');
+ }
+ return n;
+}
+
+int *countMentions(int numberOfUsers, char ***events, int eventsSize,
+ int *eventsColSize, int *returnSize) {
+ int *time = (int *)malloc(eventsSize * sizeof(int));
+ int *order = (int *)malloc(eventsSize * sizeof(int));
+ for (int i = 0; i < eventsSize; i++)
+ time[i] = str_to_num(events[i][1]);
+ for (int i = 0; i < eventsSize; i++)
+ order[i] = i;
+ for (int i = eventsSize - 1; i > 0; i--)
+ for (int j = 0; j < i; j++)
+ if (time[order[j + 1]] < time[order[j]] ||
+ (time[order[j + 1]] == time[order[j]] &&
+ events[order[j + 1]][0][0] == 'O')) {
+ int curr_time = order[j];
+ order[j] = order[j + 1];
+ order[j + 1] = curr_time;
+ }
+ int *online = (int *)calloc(numberOfUsers, sizeof(int));
+ int *mention = (int *)calloc(numberOfUsers, sizeof(int));
+ *returnSize = numberOfUsers;
+ for (int n = 0; n < eventsSize; n++) {
+ int i = order[n];
+ if (events[i][0][0] == 'M') {
+ if (events[i][2][0] == 'A') {
+ for (int j = 0; j < numberOfUsers; j++)
+ mention[j] += 1;
+ } else if (events[i][2][0] == 'H') {
+ int curr_time = str_to_num(events[i][1]);
+ for (int j = 0; j < numberOfUsers; j++) {
+ if (online[j] == 0)
+ mention[j] += 1;
+ else if (online[j] <= curr_time) {
+ online[j] = 0;
+ mention[j] += 1;
+ }
+ }
+ } else {
+ char t_id[10];
+ char *prev = &(events[i][2][0]), *space = strchr(events[i][2], ' ');
+ while (true) {
+ memset(t_id, '\0', sizeof(t_id));
+ if (!space) {
+ strcpy(t_id, prev + 2);
+ mention[str_to_num(t_id)] += 1;
+ break;
+ } else {
+ strncpy(t_id, prev + 2, (int)(space - prev - 2));
+ mention[str_to_num(t_id)] += 1;
+ prev = space + 1;
+ space = strchr(prev, ' ');
+ }
+ }
+ }
+ } else if (events[i][0][0] == 'O')
+ online[str_to_num(events[i][2])] = str_to_num(events[i][1]) + 60;
+ }
+ free(time);
+ free(order);
+ free(online);
+ free(mention);
+ return mention;
+}
+
+int main() {
+ char *e1[3][3] = {{"MESSAGE", "10", "id1 id0"},
+ {"OFFLINE", "11", "0"},
+ {"MESSAGE", "71", "HERE"}};
+ char *e2[3][3] = {{"MESSAGE", "10", "id1 id0"},
+ {"OFFLINE", "11", "0"},
+ {"MESSAGE", "12", "ALL"}};
+ char *e3[2][3] = {{"OFFLINE", "10", "0"}, {"MESSAGE", "12", "HERE"}};
+ int ecs1 = ARRAY_SIZE(e1[0]), rs1;
+ int ecs2 = ARRAY_SIZE(e2[0]), rs2;
+ int ecs3 = ARRAY_SIZE(e3[0]), rs3;
+ int *cm1 = countMentions(2, (char ***)e1, ARRAY_SIZE(e1), &ecs1, &rs1);
+ int *cm2 = countMentions(2, (char ***)e2, ARRAY_SIZE(e2), &ecs2, &rs2);
+ int *cm3 = countMentions(2, (char ***)e3, ARRAY_SIZE(e3), &ecs3, &rs3);
+ for (int i = 0; i < rs1; i++)
+ printf("%d ", cm1[i]); // expect: 2 2
+ printf("\n");
+ for (int i = 0; i < rs2; i++)
+ printf("%d ", cm2[i]); // expect: 2 2
+ printf("\n");
+ for (int i = 0; i < rs3; i++)
+ printf("%d ", cm3[i]); // expect: 0 1
+ printf("\n");
+ free(cm1);
+ free(cm2);
+ free(cm3);
+}
diff --git a/count_mentions_per_user.py b/count_mentions_per_user.py
@@ -0,0 +1,71 @@
+# 3433. Count Mentions Per User
+
+"""
+you are given an integer 'numberOfUsers' representing the total number of
+users and an array 'events' of size 'n x 3'. each 'events[i]' can be either
+of the following types: message event indicates that a set of users was
+mentioned in a message at 'timestamp' offline even indicates that the user
+'id_i' has become offline at 'timestamp_i' for 60 time units. the user will
+automatically be online again at time 'timestamp_i + 60'. return an array
+'mentions' that represents the number of mentions the user with id 'i' has
+across all 'MESSAGE' events. all users are initially online, and if a user
+goes offline or comes back online, their status change is processed before
+handling any message event that occurs at the same timestamp
+"""
+
+
+class Solution(object):
+ def countMentions(self, numberOfUsers, events):
+ """
+ :type numberOfUsers: int
+ :type events: List[List[str]]
+ :rtype: List[int]
+ """
+ mentions = [0] * numberOfUsers
+ online = [1] * numberOfUsers
+ users = range(numberOfUsers)
+ events.sort(key=lambda x: (int(x[1]), x[0] == "MESSAGE"))
+ for action, stamp, mentioned in events:
+ if action == "MESSAGE":
+ if mentioned == "ALL":
+ for user in users:
+ mentions[user] += 1
+ elif mentioned == "HERE":
+ for user in users:
+ if online[user] <= int(stamp):
+ mentions[user] += 1
+ else:
+ for id in mentioned.replace("id", "").split(" "):
+ mentions[int(id)] += 1
+ else:
+ online[int(mentioned)] = int(stamp) + 60
+ return mentions
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(
+ obj.countMentions(
+ numberOfUsers=2,
+ events=[
+ ["MESSAGE", "10", "id1 id0"],
+ ["OFFLINE", "11", "0"],
+ ["MESSAGE", "71", "HERE"],
+ ],
+ )
+ )
+ print(
+ obj.countMentions(
+ numberOfUsers=2,
+ events=[
+ ["MESSAGE", "10", "id1 id0"],
+ ["OFFLINE", "11", "0"],
+ ["MESSAGE", "12", "ALL"],
+ ],
+ )
+ )
+ print(
+ obj.countMentions(
+ numberOfUsers=2, events=[["OFFLINE", "10", "0"], ["MESSAGE", "12", "HERE"]]
+ )
+ )
