code

main.cpp

@@ -0,0 +1,60 @@
+#include <iostream>
+#include <map>
+template<typename K, typename V>
+class interval_map {
+    friend void IntervalMapTest();
+    V m_valBegin;
+    std::map<K,V> m_map;
+public:
+    // constructor associates whole range of K with val
+    interval_map(V const& val, K k_range=1000)
+    : m_valBegin(val) {
+        for(K i=0; i<k_range; ++i)m_map.insert(std::pair<K,V>(i,val));
+    }
+
+    // Assign value val to interval [keyBegin, keyEnd).
+    // Overwrite previous values in this interval.
+    // Conforming to the C++ Standard Library conventions, the interval
+    // includes keyBegin, but excludes keyEnd.
+    // If !( keyBegin < keyEnd ), this designates an empty interval,
+    // and assign must do nothing.
+    void assign( K const& keyBegin, K const& keyEnd, V const& val ) {
+        K Begin = keyBegin;
+        if(Begin < keyEnd) {
+            if(Begin < m_map.begin()->first)Begin=m_map.begin()->first;
+            auto it_begin = m_map.lower_bound(Begin);
+            if(it_begin == m_map.end() || m_map.key_comp()(Begin, (*it_begin).first)) {
+                m_map.insert(std::pair<K,V>(Begin, val));
+            }else {
+                it_begin->second = val;
+            }
+            if (it_begin != m_map.end())assign((++it_begin)->first, keyEnd, val);
+        }
+    }
+
+    // look-up of the value associated with key
+    V const& operator[]( K const& key ) const {
+        auto it=m_map.upper_bound(key);
+        if(it==m_map.begin()) {
+            return m_valBegin;
+        } else {
+            return (--it)->second;
+        }
+    }
+    void print() {
+        for(auto i : m_map)std::cerr<<"("<<i.first<<","<<i.second<<"),";
+        std::cerr<<'\n';
+    }
+};
+
+// Many solutions we receive are incorrect. Consider using a randomized test
+// to discover the cases that your implementation does not handle correctly.
+// We recommend to implement a test function that tests the functionality of
+// the interval_map, for example using a map of int intervals to char.
+
+int main() {
+    interval_map<int, char> m('A', 100);
+    m.assign(-10, 50, 'B');
+    m.print();
+    return 0;
+}