aoc

commit 104f717c4e86bb537db84a8e9e4fc4c2272dece3
parent 00b869790ebbc4afff31bc6ccc72d99b102cd2a5
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Mon,  9 Dec 2024 14:06:37 +0100

Day 9 with views::reverse

Diffstat:
M
2024/09/day09a.cpp
 | 
7
++++---
M
2024/09/day09b.cpp
 | 
17
+++++++++--------
M
2024/learned.txt
 | 
1
+
M
2024/template.cpp
 | 
1
+

4 files changed, 15 insertions(+), 11 deletions(-)
diff --git a/2024/09/day09a.cpp b/2024/09/day09a.cpp
@@ -1,6 +1,7 @@
 #include <algorithm>
 #include <iostream>
 #include <map>
+#include <ranges>
 #include <set>
 #include <sstream>
 #include <string>
@@ -16,11 +17,11 @@ int main() {
 			a.push_back(id % 2 == 0 ? id/2 : -1); // -1 = space
 
 	int j = 0;
-	for (int i = a.size()-1; i >= 0; i--) {
+	for (auto& x : a | views::reverse) {
 		while (a[j] >= 0) j++;
 		if (a[j] == -2) break;
-		a[j] = a[i];
-		a[i] = -2; // -2 = freed up
+		a[j] = x;
+		x = -2; // -2 = freed up
 	}
 
 	long long checksum = 0;
diff --git a/2024/09/day09b.cpp b/2024/09/day09b.cpp
@@ -1,6 +1,7 @@
 #include <algorithm>
 #include <iostream>
 #include <map>
+#include <ranges>
 #include <set>
 #include <sstream>
 #include <string>
@@ -21,16 +22,16 @@ int main() {
 			a.push_back(id % 2 == 0 ? id/2 : -1); // -1 = space
 	}
 
-	for (int i = file.size()-1; i >= 0; i--) {
+	for (auto& p : file | views::reverse) {
 		for (auto& f : freesp) {
-			if (f.first >= file[i].first) break;
-			if (f.second >= file[i].second) {
-				for (int k = 0; k < file[i].second; k++) {
-					a[f.first+k] = a[file[i].first+k];
-					a[file[i].first+k] = -2;
+			if (f.first >= p.first) break;
+			if (f.second >= p.second) {
+				for (int k = 0; k < p.second; k++) {
+					a[f.first+k] = a[p.first+k];
+					a[p.first+k] = -2;
 				}
-				f.first += file[i].second;
-				f.second -= file[i].second;
+				f.first += p.second;
+				f.second -= p.second;
 				break;
 			}
 		}
diff --git a/2024/learned.txt b/2024/learned.txt
@@ -7,3 +7,4 @@ List of things I learned (or refreshed) with this year's AoC.
   to assign two variables at once with a pair of references pair<int&, int&>
 * Day 5: std::find and std::replace
 * Day 8: set::insert_range(), but it is from C++23 only
+* Day 9: std::views
diff --git a/2024/template.cpp b/2024/template.cpp
@@ -1,6 +1,7 @@
 #include <algorithm>
 #include <iostream>
 #include <map>
+#include <ranges>
 #include <set>
 #include <sstream>
 #include <string>