Merge pull request #4441 from pauloscustodio/paulo-custodio

Add solutions to challenge 120

2 files changed, 103 insertions, 0 deletions

diff --git a/challenge-120/paulo-custodio/cpp/ch-1.cpp b/challenge-120/paulo-custodio/cpp/ch-1.cpp
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+++ b/challenge-120/paulo-custodio/cpp/ch-1.cpp
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+/*
+Challenge 120
+
+TASK #1 - Swap Odd/Even bits
+Submitted by: Mohammad S Anwar
+You are given a positive integer $N less than or equal to 255.
+
+Write a script to swap the odd positioned bit with even positioned bit and
+print the decimal equivalent of the new binary representation.
+
+Example
+Input: $N = 101
+Output: 154
+
+Binary representation of the given number is 01 10 01 01.
+The new binary representation after the odd/even swap is 10 01 10 10.
+The decimal equivalent of 10011010 is 154.
+
+Input: $N = 18
+Output: 33
+
+Binary representation of the given number is 00 01 00 10.
+The new binary representation after the odd/even swap is 00 10 00 01.
+The decimal equivalent of 100001 is 33.
+*/
+
+#include <iostream>
+using namespace std;
+
+int swap_bits(int n) {
+    int out = 0;
+    int shift = 0;
+    while (n > 0) {
+        if ((n & 1) != 0) { out |= 2 << shift; }
+        if ((n & 2) != 0) { out |= 1 << shift; }
+        n >>= 2;
+        shift += 2;
+    }
+    return out;
+}
+
+int main(int argc, char* argv[]) {
+    int n = 0;
+    if (argc == 2) n = atoi(argv[1]);
+    cout << swap_bits(n) << endl;
+}
diff --git a/challenge-120/paulo-custodio/cpp/ch-2.cpp b/challenge-120/paulo-custodio/cpp/ch-2.cpp
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+/*
+Challenge 120
+
+TASK #2 › Clock Angle
+Submitted by: Mohammad S Anwar
+You are given time $T in the format hh:mm.
+
+Write a script to find the smaller angle formed by the hands of an analog
+clock at a given time.
+
+HINT: A analog clock is divided up into 12 sectors. One sector represents 30
+degree (360/12 = 30).
+
+Example
+Input: $T = '03:10'
+Output: 35 degree
+
+The distance between the 2 and the 3 on the clock is 30 degree.
+For the 10 minutes i.e. 1/6 of an hour that have passed.
+The hour hand has also moved 1/6 of the distance between the 3 and the 4,
+which adds 5 degree (1/6 of 30).
+The total measure of the angle is 35 degree.
+
+Input: $T = '04:00'
+Output: 120 degree
+*/
+
+#include <iostream>
+#include <sstream>
+#include <string>
+using namespace std;
+
+bool parse_time(const string& hhmm, int* hh, int* mm) {
+    *hh = *mm = 0;
+    istringstream iss(hhmm);
+    char c;
+    if (!(iss >> *hh)) return false;
+    if (!(iss >> c) || c != ':') return false;
+    if (!(iss >> *mm)) return false;
+    return true;
+}
+
+int clock_angle(int hh, int mm) {
+    int mm_angle = mm*360/60;
+    int hh_angle = (hh % 12)*360/12 + mm_angle/12;
+    int angle = abs(hh_angle - mm_angle);
+    if (angle > 180) { angle = 360 - angle; }
+    return angle;
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) return EXIT_FAILURE;
+    int hh, mm;
+    if (!parse_time(argv[1], &hh, &mm)) return EXIT_FAILURE;
+    int angle = clock_angle(hh, mm);
+    cout << angle << endl;
+}