Merge pull request #3456 from pauloscustodio/098

098

2 files changed, 145 insertions, 0 deletions

diff --git a/challenge-098/paulo-custodio/cpp/ch-1.cpp b/challenge-098/paulo-custodio/cpp/ch-1.cpp
new file mode 100644
index 0000000000..0d3f5c0cc3
--- /dev/null
+++ b/challenge-098/paulo-custodio/cpp/ch-1.cpp
@@ -0,0 +1,76 @@
+/*
+Challenge 098
+
+TASK #1 › Read N-characters
+Submitted by: Mohammad S Anwar
+You are given file $FILE.
+
+Create subroutine readN($FILE, $number) returns the first n-characters and
+moves the pointer to the (n+1)th character.
+
+Example:
+Input: Suppose the file (input.txt) contains "1234567890"
+Output:
+    print readN("input.txt", 4); # returns "1234"
+    print readN("input.txt", 4); # returns "5678"
+    print readN("input.txt", 4); # returns "90"
+*/
+
+#include <algorithm>
+#include <array>
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <cassert>
+#include <cstring>
+
+// store list of open files
+class Files {
+public:
+    std::string readN(const std::string filename, int n) {
+        std::ifstream& ifs = add_file(filename);
+        char* buffer = new char[n + 1];
+        memset(buffer, 0, n + 1);
+        ifs.read(buffer, n);
+        auto text = std::string(buffer);
+        delete[] buffer;
+        return text;
+    }
+
+private:
+    // store std::ifstream in a pre-aloocated array as storing pointers to
+    // std::ifstream in an unordered_map was causing a heap corruption in
+    // GCC - probably a compiler/stdlib bug
+    static const int MAX_FILES = 20;
+    std::array<std::ifstream, MAX_FILES> files;
+    std::array<std::string, MAX_FILES> filenames;
+    size_t num_files{ 0 };
+
+    std::ifstream& add_file(const std::string filename) {
+        auto end = filenames.begin() + num_files;
+        auto found = std::find(filenames.begin(), end, filename);
+        if (found != end) {   // found in filename
+            size_t i = std::distance(filenames.begin(), found);
+            return files[i];
+        }
+        else {                                      // not found, must create new entry
+            if (num_files >= MAX_FILES) {
+                std::cerr << "too many files" << std::endl;
+                exit(EXIT_FAILURE);
+            }
+            filenames[num_files] = filename;
+            files[num_files].open(filename);
+            if (!files[num_files].is_open()) {
+                std::cerr << "open file " << filename << " failed" << std::endl;
+                exit(EXIT_FAILURE);
+            }
+            return files[num_files++];
+        }
+    }
+};
+
+int main(int argc, char* argv[]) {
+    Files f;
+    for (int i = 1; i + 1 < argc; i += 2)
+        std::cout << f.readN(argv[i], atoi(argv[i + 1])) << std::endl;
+}
diff --git a/challenge-098/paulo-custodio/cpp/ch-2.cpp b/challenge-098/paulo-custodio/cpp/ch-2.cpp
new file mode 100644
index 0000000000..310347f3ab
--- /dev/null
+++ b/challenge-098/paulo-custodio/cpp/ch-2.cpp
@@ -0,0 +1,69 @@
+/*
+Challenge 098
+
+TASK #2 › Search Insert Position
+Submitted by: Mohammad S Anwar
+You are given a sorted array of distinct integers @N and a target $N.
+
+Write a script to return the index of the given target if found
+otherwise place the target in the sorted array and return the index.
+
+Example 1:
+Input: @N = (1, 2, 3, 4) and $N = 3
+Output: 2 since the target 3 is in the array at the index 2.
+Example 2:
+Input: @N = (1, 3, 5, 7) and $N = 6
+Output: 3 since the target 6 is missing and should be placed at
+the index 3.
+Example 3:
+Input: @N = (12, 14, 16, 18) and $N = 10
+Output: 0 since the target 10 is missing and should be placed at
+the index 0.
+Example 4:
+Input: @N = (11, 13, 15, 17) and $N = 19
+Output: 4 since the target 19 is missing and should be placed at
+the index 4.
+*/
+
+#include <algorithm>
+#include <iostream>
+#include <vector>
+
+int search_index(std::vector<int>& nums, int n) {
+    auto it = std::lower_bound(nums.begin(), nums.end(), n);
+    if (it == nums.end()) {             // not found
+        nums.push_back(n);
+        return nums.size() - 1;
+    }
+    else if (*it != n) {                // found an higher value
+        int index = std::distance(nums.begin(), it);    // insert may move memory
+        nums.insert(it, n);
+        return index;
+    }
+    else {                              // found value
+        return std::distance(nums.begin(), it);
+    }
+}
+
+int main(int argc, char* argv[]) {
+    if (argc < 2) {
+        std::cerr << "Usage: ch-2 N n0 n1 n2..." << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    std::vector<int> nums;
+    int n = atoi(argv[1]);
+    for (int i = 2; i < argc; i++)
+        nums.push_back(atoi(argv[i]));
+
+    int pos = search_index(nums, n);
+
+    std::cout << pos << std::endl;
+
+    const char* sep = "(";
+    for (auto& i : nums) {
+        std::cout << sep << i;
+        sep = ", ";
+    }
+    std::cout << ")" << std::endl;
+}