1496. Path Crossing - Easy
문제
Given a string path, where path[i] = ‘N’, ‘S’, ‘E’ or ‘W’, each representing moving one unit north, south, east, or west, respectively. You start at the origin (0, 0) on a 2D plane and walk on the path specified by path.
Return true if the path crosses itself at any point, that is, if at any time you are on a location you have previously visited. Return false otherwise.
제한사항`
- 1 <= path.length <= 104
- path[i] is either ‘N’, ‘S’, ‘E’, or ‘W’.
입출력 예
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Example 1:
Input: path = "NES"
Output: false
Explanation: Notice that the path doesn't cross any point more than once.
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Example 2:
Input: path = "NESWW"
Output: true
Explanation: Notice that the path visits the origin twice.
풀이
- Hash
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class Solution {
struct Point {
int x;
int y;
};
public:
bool isPathCrossing(string path) {
Point point = {0, 0};
std::map<int, std::map<int, bool>> item;
item[0][0] = true;
for (const char& c : path) {
if (c == 'N') {
++point.y;
} else if (c == 'S') {
--point.y;
} else if (c == 'E') {
++point.x;
} else {
--point.x;
}
if (item[point.x][point.y]) {
return true;
}
item[point.x][point.y] = true;
}
return false;
}
};