uva 12299 - RMQ with Shifts(线段树)

题目链接：uva 12299 - RMQ with Shifts

题目大意：给定一个数组，有两种操作。
query l r：查询l到r之间的最小值
shift x1 x2 x3:将下标为x1 x2 x3的位置上的数循环移动一个长度。

解题思路：线段树维护最小值，因为每条命令的长度不会超过30，所以循环移动的数并不会很多，用单点修改去处理。

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
#define lson(x) ((x)<<1)
#define rson(x) (((x)<<1)+1)
const int maxn = 1e5+5;

struct Node {
int l, r, val;
Node (int l = 0, int r = 0, int val = 0) {
this->set(l, r, val);
}
void set (int l, int r, int val) {
this->l = l;
this->r = r;
this->val = val;
}
}node[maxn*4];

int N, M, arr[maxn];

void pushup (int u) {
int val = min(node[lson(u)].val, node[rson(u)].val);
node[u].set(node[lson(u)].l, node[rson(u)].r, val);
}

void build_segTree (int u, int l, int r) {

if (l == r) {
node[u].set(l, r, arr[l]);
return;
}

int mid = (l + r) / 2;
build_segTree(lson(u), l, mid);
build_segTree(rson(u), mid + 1, r);
pushup(u);
}

void insert_segTree (int u, int pos, int v) {
if (node[u].l == pos && node[u].r == pos) {
node[u].val = v;
return;
}

int mid = (node[u].l + node[u].r) / 2;

if (pos <= mid)
insert_segTree(lson(u), pos, v);
else
insert_segTree(rson(u), pos, v);
pushup(u);
}

int query_segTree (int u, int l, int r) {
if (l <= node[u].l && node[u].r <= r)
return node[u].val;

int mid = (node[u].l + node[u].r) / 2;

if (r <= mid)
return query_segTree(lson(u), l, r);
else if (l > mid)
return query_segTree(rson(u), l, r);
else
return min(query_segTree(lson(u), l, r), query_segTree(rson(u), l, r));
}

void get_number (int& n, int* num, char* s) {
n = 0;
int len = strlen(s), u = 0;

for (int i = 0; i < len; i++) {
if (s[i] >= '0' && s[i] <= '9')
u = u * 10 + s[i] - '0';
else if (s[i] == ',' || s[i] == ')') {
num[n++] = u;
u = 0;
} else
u = 0;
}
}

void solve () {
int n, num[50];
char order[50];

scanf("%s", order);
get_number(n, num, order);

if (order[0] == 's') {
int tmp = arr[num[0]];
for (int i = 0; i < n - 1; i++) {
insert_segTree(1, num[i], arr[num[i+1]]);
arr[num[i]] = arr[num[i+1]];
}
insert_segTree(1, num[n-1], tmp);
arr[num[n-1]] = tmp;
} else if (order[0] == 'q')
printf("%d\n", query_segTree(1, num[0], num[1]));
}

int main () {
while (scanf("%d%d", &N, &M) == 2) {
for (int i = 1; i <= N; i++)
scanf("%d", &arr[i]);
build_segTree(1, 1, N);

for (int i = 0; i < M; i++)
solve();
}
return 0;
}