逆序数 pku 1804 pku 2299 sgu 180

pku 1804

归并排序

/*
 * poj1804.c
 *
 *  Created on: 2011-9-29
 *      Author: bjfuwangzhu
 */

#include<stdio.h>
#define nmax 1010
int num[nmax], temp[nmax];
int res;
void merge(int left, int mid, int right) {
    int i, j, k;
    i = left, j = mid + 1, k = 0;
    while (i <= mid && j <= right) {
        if (num[j] < num[i]) {
            temp[k++] = num[j++];
            res += mid - i + 1;
        } else {
            temp[k++] = num[i++];
        }
    }
    while (i <= mid) {
        temp[k++] = num[i++];
    }
    while (j <= right) {
        temp[k++] = num[j++];
    }
    for (i = 0, j = left; j <= right; j++, i++) {
        num[j] = temp[i];
    }
}
void mergeSort(int left, int right) {
    int mid;
    if (left < right) {
        mid = (left + right) >> 1;
        mergeSort(left, mid);
        mergeSort(mid + 1, right);
        merge(left, mid, right);
    }
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int t, n, i, j;
    scanf("%d", &t);
    for (i = 1; i <= t; i++) {
        scanf("%d", &n);
        for (j = 0; j < n; j++) {
            scanf("%d", num + j);
        }
        res = 0;
        mergeSort(0, n - 1);
        printf("Scenario #%d:\n%d\n", i, res);
        if (i < t) {
            printf("\n");
        }
    }
    return 0;
}

树状数组

//C 树状数组

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define nmax 1010
#define lowbit(x) x&(-x)
typedef struct node {
    int val, id;
} node;
node Node[nmax];
int sum[nmax], num[nmax];
void update(int i, int val, int n) {
    while (i <= n) {
        sum[i] += val;
        i += lowbit(i);
    }
}
int getSum(int i) {
    int res;
    res = 0;
    while (i > 0) {
        res += sum[i];
        i -= lowbit(i);
    }
    return res;
}
int cmp(const void *a, const void *b) {
    node n = *(node *) a;
    node m = *(node *) b;
    return n.val - m.val;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int t, n, temp, i, j, k, res;
    scanf("%d", &t);
    for (i = 1; i <= t; i++) {
        scanf("%d", &n);
        for (j = 0; j < n; j++) {
            scanf("%d", &Node[j].val);
            Node[j].id = j;
        }
        qsort(Node, n, sizeof(Node[0]), cmp);
        memset(sum, 0, sizeof(sum));
        num[Node[0].id] = 1, k = 1, temp = Node[0].val;
        for (j = 1; j < n; j++) {
            if (temp != Node[j].val) {
                temp = Node[j].val;
                num[Node[j].id] = ++k;
            } else {
                num[Node[j].id] = k;
            }
        }
        for (j = n - 1, res = 0; j >= 0; j--) {
            update(num[j], 1, n + 1);
            res += getSum(num[j] - 1);
        }
        printf("Scenario #%d:\n%d\n", i, res);
        if (i < t) {
            printf("\n");
        }
    }
    return 0;
}

//C++ 树状数组

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define nmax 1010
#define lowbit(x) x&(-x)
struct node {
    int val, id;
    bool operator<(const node &m) const {
        return val < m.val;
    }
};
node Node[nmax];
int sum[nmax], num[nmax];
void update(int i, int val, int n) {
    while (i <= n) {
        sum[i] += val;
        i += lowbit(i);
    }
}
int getSum(int i) {
    int res;
    res = 0;
    while (i > 0) {
        res += sum[i];
        i -= lowbit(i);
    }
    return res;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int t, n, temp, i, j, k, res;
    scanf("%d", &t);
    for (i = 1; i <= t; i++) {
        scanf("%d", &n);
        for (j = 0; j < n; j++) {
            scanf("%d", &Node[j].val);
            Node[j].id = j;
        }
        sort(Node, Node + n);
        memset(sum, 0, sizeof(sum));
        num[Node[0].id] = 1, k = 1, temp = Node[0].val;
        for (j = 1; j < n; j++) {
            if (temp != Node[j].val) {
                temp = Node[j].val;
                num[Node[j].id] = ++k;
            } else {
                num[Node[j].id] = k;
            }
        }
        for (j = n - 1, res = 0; j >= 0; j--) {
            update(num[j], 1, n + 1);
            res += getSum(num[j] - 1);
        }
        printf("Scenario #%d:\n%d\n", i, res);
        if (i < t) {
            printf("\n");
        }
    }
    return 0;
}

pku 2299

/*
 * poj2299.c
 *
 *  Created on: 2011-9-29
 *      Author: bjfuwangzhu
 */

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define nmax 500001
#define LL long long
#define lowbit(x) x&(-x)
typedef struct node {
    int val, id;
} node;
node Node[nmax];
int n;
int sum[nmax];
void update(int i, int val) {
    while (i <= n) {
        sum[i] += val;
        i += lowbit(i);
    }
}
int getSum(int i) {
    LL res;
    res = 0;
    while (i > 0) {
        res += sum[i];
        i -= lowbit(i);
    }
    return res;
}
int cmp(const void *a, const void *b) {
    node n = *(node *) a;
    node m = *(node *) b;
    return n.val - m.val;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int i;
    LL res;
    while (~scanf("%d", &n) && n) {
        for (i = 0; i < n; i++) {
            scanf("%d", &Node[i].val);
            Node[i].id = i + 1;
        }
        qsort(Node, n, sizeof(Node[0]), cmp);
        memset(sum, 0, sizeof(sum));
        for (i = 0, res = 0; i < n; i++) {
            res += i - getSum(Node[i].id);
            update(Node[i].id, 1);
        }
        printf("%I64d\n", res);
    }
    return 0;
}

sgu 180

归并排序

/*
 * sgu180.c
 *
 *  Created on: 2011-9-29
 *      Author: bjfuwangzhu
 */

#include<stdio.h>
#include<string.h>
#define nmax 65538
#define LL long long
int num[nmax], temp[nmax];
LL res;
int n;
void merge(int left, int mid, int right) {
    int i, j, k;
    i = left, j = mid + 1, k = 0;
    while (i <= mid && j <= right) {
        if (num[j] < num[i]) {
            temp[k++] = num[j++];
            res += (mid - i + 1);
        } else {
            temp[k++] = num[i++];
        }
    }
    while (i <= mid) {
        temp[k++] = num[i++];
    }
    while (j <= right) {
        temp[k++] = num[j++];
    }
    for (i = 0; i < k; i++) {
        num[left++] = temp[i];
    }
}
void mergeSort(int left, int right) {
    int mid;
    if (left < right) {
        mid = (left + right) >> 1;
        mergeSort(left, mid);
        mergeSort(mid + 1, right);
        merge(left, mid, right);
    }
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int i;
    while (~scanf("%d", &n)) {
        for (i = 0; i < n; i++) {
            scanf("%d", num + i);
        }
        res = 0;
        mergeSort(0, n - 1);
        printf("%I64d\n", res);
    }
    return 0;
}

树状数组C++版AC

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
using namespace std;
#define nmax 65550
#define LL long long
#define lowbit(x) x&(-x)
typedef struct node {
    int val, id;
    bool operator<(const node &m) const {
        return val < m.val;
    }
} node;
node Node[nmax];
int sum[nmax], num[nmax];
void update(int i, int val, int n) {
    while (i <= n) {
        sum[i] += val;
        i += lowbit(i);
    }
}
int getSum(int i) {
    int res;
    res = 0;
    while (i > 0) {
        res += sum[i];
        i -= lowbit(i);
    }
    return res;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int i, temp, k, n;
    LL res;
    while (~scanf("%d", &n)) {
        for (i = 0; i < n; i++) {
            scanf("%d", &Node[i].val);
            Node[i].id = i;
        }
        sort(Node, Node + n);
        memset(sum, 0, sizeof(sum));
        for (i = 0, temp = -1, k = 0; i < n; i++) {
            if (temp != Node[i].val) {
                num[Node[i].id] = ++k;
                temp = Node[i].val;
            } else {
                num[Node[i].id] = k;
            }
        }
        for (i = 0, res = 0; i < n; i++) {
            res += i - getSum(num[i]);
            update(num[i], 1, n + 1);
        }
        printf("%I64d\n", res);
    }
    return 0;
}

树状数组C版超时

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define nmax 65550
#define LL long long
#define lowbit(x) x&(-x)
typedef struct node {
    int val, id;
} node;
node Node[nmax];
int sum[nmax], num[nmax];
void update(int i, int val, int n) {
    while (i <= n) {
        sum[i] += val;
        i += lowbit(i);
    }
}
int getSum(int i) {
    LL res;
    res = 0;
    while (i > 0) {
        res += sum[i];
        i -= lowbit(i);
    }
    return res;
}
int cmp(const void *a, const void *b) {
    node n = *(node *) a;
    node m = *(node *) b;
    return n.val - m.val;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int i, temp, k, n;
    LL res;
    while (~scanf("%d", &n)) {
        for (i = 0; i < n; i++) {
            scanf("%d", &Node[i].val);
            Node[i].id = i;
        }
        qsort(Node, n, sizeof(Node[0]), cmp);
        memset(sum, 0, sizeof(sum));
        for (i = 0, temp = -1, k = 0; i < n; i++) {
            if (temp != Node[i].val) {
                num[Node[i].id] = ++k;
                temp = Node[i].val;
            } else {
                num[Node[i].id] = k;
            }
        }
        for (i = n - 1, res = 0; i >= 0; i--) {
            update(num[i], 1, n + 1);
            res += getSum(num[i] - 1);
        }
        printf("%I64d\n", res);
    }
    return 0;
}

请路过的大牛指导，为什么使用C过不了，C++ 就过了，仅仅是排序换了一个（从qsort到sort），就可以了，不懂为什么？