Codeforces 461C Appleman and a Sheet of Paper(類比)

標籤：style   http   color   os   io   ar   for   sp   amp   

題目連結：Codeforces 461C Appleman and a Sheet of Paper

題目大意：就是一個疊被子的過程，穿插著詢問一段區間上被子的單位厚度。

解題思路：用首碼和數組類比即可。因為對於折超過一半的處理為將令一半疊上來，所以需要變數記錄當前被子的正反狀態。處理好下標關係即可。

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int maxn = 1e6+5;int N, Q, W[maxn];int main () {    scanf("%d%d", &N, &Q);    for (int i = 1; i <= N; i++)        W[i] = i;    bool flag = false;    int k, l, r;    int n = N, bw = 0;    while (Q--) {        scanf("%d%d", &k, &l);        if (k == 1) {            if (l > n - l) {                flag = !flag;                l = n - l;            }            if (flag) {                for (int i = 0; i < l; i++)                    W[bw + n - l - i] += N - W[bw + n - l + i];            } else {                bw += l;                for (int i = 0; i < l; i++)                    W[bw + i] -= W[bw - i];            }            n -= l;        } else {            scanf("%d", &r);            if (flag) {                int tmp = n - r;                r = n - l;                l = tmp;            }            printf("%d\n", W[bw + r] - W[bw + l]);        }    }    return 0;}

Codeforces 461C Appleman and a Sheet of Paper(類比)