Dec22: vector, map manipulation

Author: aucker

daily/Dec12.go

@@ -0,0 +1,13 @@
+func maxSpending(values [][]int) (ans int64) {
+	m, n := len(values), len(values[0])
+	a := make([]int, 0, m * n) // reserve space
+	for _, row := range values {
+		a = append(a, row...)
+	}
+	slices.Sort(a)
+
+	for i, x := range a {
+		ans += int64(x) * int64(i + 1)
+	}
+	return
+}

daily/Dec22.cc

@@ -0,0 +1,42 @@
+#include <unordered_map>
+#include <vector>
+using namespace std;
+
+class Solution {
+ public:
+  int stepToOne(int n) {
+    int res = 0;
+    if (n == 1) return 0;
+    while (n != 1) {
+      if (n % 2 == 0) {
+        n /= 2;
+      } else {
+        n = n * 3 + 1;
+      }
+      res++;
+    }
+    return res;
+  }
+
+  /**
+   * LC1387: Sort Integers by the power value [E]
+   * Basic pair, map
+   */
+  int getKth(int lo, int hi, int k) {
+    unordered_map<int, int> nmap;
+    for (int i = lo; i <= hi; i++) {
+      nmap[i] = stepToOne(i);
+    }
+    vector<pair<int, int>> sortedVector(nmap.begin(), nmap.end());
+
+    sort(sortedVector.begin(), sortedVector.end(),
+         [](const pair<int, int>& le, const pair<int, int>& ri) {
+           if (le.second == ri.second) {
+             return le.first < ri.first;
+           }
+           return le.second < ri.second;
+         });
+
+    return sortedVector[k - 1].first;
+  }
+};