Update minimum-knight-moves.cpp

kamyu104 · web-flow · commit 483adf577b82 · 2019-09-22T19:27:25.000+08:00
diff --git a/C++/minimum-knight-moves.cpp b/C++/minimum-knight-moves.cpp
@@ -36,10 +36,10 @@ class Solution {
         if (x < y) {
             swap(x, y);
         }
-        unordered_map<pair<int, int>, int, PairHash<int>> lookup =
+        static const unordered_map<pair<int, int>, int, PairHash<int>> lookup =
             {{{0, 0}, 0}, {{1, 0}, 3}, {{2, 2}, 4}};  // special cases
         if (lookup.count({x, y})) {
-            return lookup[{x, y}];
+            return lookup.at({x, y});
         }
         const auto& delta = x - y;
         if (y > delta) {  // if 2y > x, every period 3 of y with same delta is increased by 2

Original file line number	Diff line number	Diff line change
`@@ -36,10 +36,10 @@ class Solution {`
`36`	`36`	`if (x < y) {`
`37`	`37`	`swap(x, y);`
`38`	`38`	`}`
`39`		`- unordered_map<pair<int, int>, int, PairHash<int>> lookup =`
	`39`	`+ static const unordered_map<pair<int, int>, int, PairHash<int>> lookup =`
`40`	`40`	`{{{0, 0}, 0}, {{1, 0}, 3}, {{2, 2}, 4}}; // special cases`
`41`	`41`	`if (lookup.count({x, y})) {`
`42`		`- return lookup[{x, y}];`
	`42`	`+ return lookup.at({x, y});`
`43`	`43`	`}`
`44`	`44`	`const auto& delta = x - y;`
`45`	`45`	`if (y > delta) { // if 2y > x, every period 3 of y with same delta is increased by 2`