LeetCode:641. Design Circular Deque設計迴圈雙端佇列(C語言)
阿新 • • 發佈:2020-12-29
技術標籤:LeetCode
題目描述:
設計實現雙端佇列。
你的實現需要支援以下操作:
MyCircularDeque(k):建構函式,雙端佇列的大小為k。 insertFront():將一個元素新增到雙端佇列頭部。 如果操作成功返回 true。 insertLast():將一個元素新增到雙端佇列尾部。如果操作成功返回 true。 deleteFront():從雙端佇列頭部刪除一個元素。 如果操作成功返回 true。 deleteLast():從雙端佇列尾部刪除一個元素。如果操作成功返回 true。 getFront():從雙端佇列頭部獲得一個元素。如果雙端佇列為空,返回 -1。 getRear():獲得雙端佇列的最後一個元素。 如果雙端佇列為空,返回 -1。 isEmpty():檢查雙端佇列是否為空。 isFull():檢查雙端佇列是否滿了。
示例:
MyCircularDeque circularDeque = new MycircularDeque(3); // 設定容量大小為3
circularDeque.insertLast(1); // 返回 true
circularDeque.insertLast(2); // 返回 true
circularDeque.insertFront(3); // 返回 true
circularDeque.insertFront(4); // 已經滿了,返回 false
circularDeque.getRear(); // 返回 2
circularDeque.isFull(); // 返回 true
circularDeque.deleteLast(); // 返回 true
circularDeque.getFront(); // 返回 4
提示:
所有值的範圍為 [1, 1000]
操作次數的範圍為 [1, 1000]
請不要使用內建的雙端佇列庫。
來源:力扣(LeetCode)
連結:https://leetcode-cn.com/problems/design-circular-deque
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解答:
typedef struct {
int *arr;
int head;
int tail;
int size;
} MyCircularDeque;
bool myCircularDequeIsFull(MyCircularDeque* obj) ;
bool myCircularDequeIsEmpty(MyCircularDeque* obj) ;
/** Initialize your data structure here. Set the size of the deque to be k. */
MyCircularDeque* myCircularDequeCreate(int k) {
MyCircularDeque *obj = malloc(sizeof(MyCircularDeque) * (k+1));
obj->arr = malloc(sizeof(int) * (k+1));
obj->head = 0;
obj->tail = 0;
obj->size = k + 1;
return obj;
}
/** Adds an item at the front of Deque. Return true if the operation is successful. */
bool myCircularDequeInsertFront(MyCircularDeque* obj, int value) {
if ( myCircularDequeIsFull(obj)) return false;
int pos = (obj->head+obj->size-1) % obj->size;
obj->arr[pos] = value;
obj->head = pos;
return true;
}
/** Adds an item at the rear of Deque. Return true if the operation is successful. */
bool myCircularDequeInsertLast(MyCircularDeque* obj, int value) {
if ( myCircularDequeIsFull(obj)) return false;
obj->arr[obj->tail] = value;
obj->tail = (obj->tail+1) % obj->size;
return true;
}
/** Deletes an item from the front of Deque. Return true if the operation is successful. */
bool myCircularDequeDeleteFront(MyCircularDeque* obj) {
if ( myCircularDequeIsEmpty(obj)) return false;
obj->head = (obj->head+1) % obj->size;
return true;
}
/** Deletes an item from the rear of Deque. Return true if the operation is successful. */
bool myCircularDequeDeleteLast(MyCircularDeque* obj) {
if ( myCircularDequeIsEmpty(obj)) return false;
obj->tail = (obj->tail-1+obj->size) % obj->size;
return true;
}
/** Get the front item from the deque. */
int myCircularDequeGetFront(MyCircularDeque* obj) {
if ( myCircularDequeIsEmpty(obj) ) return -1;
return obj->arr[obj->head];
}
/** Get the last item from the deque. */
int myCircularDequeGetRear(MyCircularDeque* obj) {
if ( myCircularDequeIsEmpty(obj) ) return -1;
int pos = (obj->tail+obj->size-1) % obj->size;
return obj->arr[pos];
}
/** Checks whether the circular deque is empty or not. */
bool myCircularDequeIsEmpty(MyCircularDeque* obj) {
return (obj->head == obj->tail) ? true : false;
}
/** Checks whether the circular deque is full or not. */
bool myCircularDequeIsFull(MyCircularDeque* obj) {
return (obj->head == (obj->tail+1) % obj->size) ? true : false;
}
void myCircularDequeFree(MyCircularDeque* obj) {
free(obj->arr);
free(obj);
return ;
}
/**
* Your MyCircularDeque struct will be instantiated and called as such:
* MyCircularDeque* obj = myCircularDequeCreate(k);
* bool param_1 = myCircularDequeInsertFront(obj, value);
* bool param_2 = myCircularDequeInsertLast(obj, value);
* bool param_3 = myCircularDequeDeleteFront(obj);
* bool param_4 = myCircularDequeDeleteLast(obj);
* int param_5 = myCircularDequeGetFront(obj);
* int param_6 = myCircularDequeGetRear(obj);
* bool param_7 = myCircularDequeIsEmpty(obj);
* bool param_8 = myCircularDequeIsFull(obj);
* myCircularDequeFree(obj);
*/
執行結果:
Notes:
參考官方文件:https://leetcode-cn.com/problems/design-circular-deque/solution/cyu-yan-shi-xian-40ms-by-xu-zhou-geng/