1. #include<iostream>
2. using namespace std;
3. const int N = 10010;
4. int n, k;
5. int q[N];
6. 
7. int quick_sort(int l, int r, int k) {
8.  if (l >= r) {
9.    return q[l];
10.   }
11.   int i = l - 1, j = r + 1,x=q[l+r>>1];
12.   while (i < j) {
13.     do {
14.       i++;
15.     } while (q[i] < x);
16.     do{
17.       j--;
18.     }while (q[j] > x);
19.     if (i < j) {
20.       swap(q[i], q[j]);
21.     }
22.   }
23.   int sl = j - l + 1;
24.   if (k<=sl) {
25.     //递归左区间
26.     return quick_sort(l, j, k);
27.   }
28.   return quick_sort(j + 1, r, k-sl);
29. }
30. 
31. int main(void) {
32.   cin >> n >> k;
33.   for (int i = 0; i < n; i++) {
34.     cin >> q[i];
35.   }
36.   cout << quick_sort(0, n - 1, k) << endl;
37.   return 0;
38. }

1. #include<iostream>
2. using namespace std;
3. const int N = 100010;
4. int q[N], tmp[N];
5. int n;
6. 
7. long long merge_sort(int l, int r) {
8.  if (l >= r) {
9.    return 0;
10.   }
11.   int mid = l + r >> 1;
12.   long long res = merge_sort(l, mid) + merge_sort(mid + 1, r);
13. 
14.   int k = 0, i = l, j = mid + 1;
15.   while (i <= mid && j <= r) {
16.     if (q[i] <= q[j]) {
17.       tmp[k++] = q[i++];
18.     }
19.     else {
20.       tmp[k++] = q[j++];
21.       res += mid - i + 1;
22.     }
23.   }
24.   while (i <= mid) {
25.     tmp[k++] = q[i++];
26.   }
27.   while (j <= r) {
28.     tmp[k++] = q[j++];
29.   }
30.   for (int i = l, j = 0; i <= r; i++, j++) {
31.     q[i] = tmp[j];
32.   }
33.   return res;
34. }
35. //6
36. //2 3 4 5 6 1
37. int main(void) {
38.   cin >> n;
39.   for (int i = 0; i < n; i++) {
40.     cin >> q[i];
41.   }
42.   cout << merge_sort(0, n - 1) << endl;
43.   return 0;
44. }

1. #include<iostream>
2. using namespace std;
3. #define eps 1e-8
4. int main(void) {
5.  double x;
6.  cin >> x;
7.  double l = -10000, r = 100000;
8.  while (r - l > eps) {
9.    double mid = (l + r) / 2;
10.     if (mid * mid * mid >= x) {
11.       r = mid;
12.     }
13.     else {
14.       l = mid;
15.     }
16.   }
17.   printf("%lf", l);
18.   return 0;
19. }

1. #include<iostream>
2. using namespace std;
3. 
4. const int N = 100010;
5. int n,m;
6. int a[N], s[N];
7. 
8. int main(void) {
9.  cin >> n >> m;
10.   for (int i = 1; i <= n; i++) {
11.     cin >> a[i];
12.   }
13.   //求前缀和
14.   for (int i = 1; i <= n; i++) {
15.     s[i] = s[i - 1] + a[i];
16.   }
17.   while (m--) {
18.     int l, r;
19.     cin >> l >> r;
20.     cout << s[r] - s[l - 1] << endl; 
21.   }
22.   return 0;
23. }

1. #include<iostream>
2. using namespace std;
3. const int N = 1010;
4. int a[N][N], s[N][N];
5. int n, m, q;
6. 
7. int main(void) {
8.  scanf("%d %d %d", &n, &m, &q);
9.  for (int i = 1; i <= n; i++) {
10.     for (int j = 1; j <= m; j++) {
11.       scanf("%d", &a[i][j]);
12.     }
13.   }
14.   //初始化前缀和
15.   for (int i = 1; i <= n; i++) {
16.     for (int j = 1; j <= m; j++) {
17.       s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + a[i][j];
18.     }
19.   }
20.   while (q--) {
21.     int x1, y1, x2, y2;
22.     scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
23.     printf("%d\n", s[x2][y2] - s[x1 - 1][y2] - s[x2][y1 - 1] + s[x1 - 1][y1 - 1]);
24.   }
25.   return 0;
26. }

1. #include<iostream>
2. using namespace std;
3. const int N = 10010;
4. int n, m;
5. int a[N], b[N];
6. 
7. void insert(int l, int r, int c) {
8.  b[l] += c;
9.  b[r + 1] -= c;
10. }
11. 
12. int main(void) {
13.   scanf("%d %d", &n, &m);
14.   for (int i = 1; i <= n; i++) {
15.     scanf("%d", &a[i]);
16.   }
17.   //构造差分数组
18.   for (int i = 1; i <= n; i++) {
19.     insert(i, i, a[i]);
20.   }
21.   while (m--) {
22.     int l, r, c;
23.     scanf("%d %d %d", &l, &r, &c);
24.     insert(l, r, c);
25.   }
26.   //求出对区间操作之后的前缀和
27.   for (int i = 1; i <= n; i++) {
28.     a[i] = a[i - 1] + b[i];
29.   }
30.   for (int i = 1; i <= n; i++) {
31.     printf("%d ", a[i]);
32.   }
33.   return 0;
34. }

1. #include<iostream>
2. using namespace std;
3. const int N = 1010;
4. int a[N][N], b[N][N];
5. int n, m, q;
6. 
7. void insert(int x1, int y1, int x2, int y2, int c) {
8.  b[x1][y1] += c;
9.  b[x1][y2+1] -= c;
10.   b[x2+1][y1] -= c;
11.   b[x2 + 1][y2 + 1] += c;
12. }
13. 
14. int main(void) {
15.   scanf("%d%d%d", &n, &m, &q);
16.   for (int i = 1; i <= n; i++) {
17.     for (int j = 1; j <= m; j++) {
18.       scanf("%d", &a[i][j]);
19.     }
20.   }
21.   //构造差分数组
22.   for (int i = 1; i <= n; i++) {
23.     for (int j = 1; j <= m; j++) {
24.       insert(i, j, i, j, a[i][j]);
25.     }
26.   }
27.   while (q--) {
28.     int x1, x2, y1, y2,c;
29.     scanf("%d %d %d %d %d", &x1, &y1, &x2, &y2, &c);
30.     insert(x1, y1, x2, y2, c);
31.   }
32.   for (int i = 1; i <= n; i++) {
33.     for (int j = 1; j <= m; j++) {
34.       a[i][j] = a[i - 1][j] + a[i][j - 1] - a[i - 1][j - 1] + b[i][j];
35.     }
36.   }
37.   for (int i = 1; i <= n; i++) {
38.     for (int j = 1; j <= m; j++) {
39.       printf("%d ", a[i][j]);
40.     }
41.     printf("\n");
42.   }
43.   return 0;
44. }