题目大意：Codeforces 444C DZY Loves Colors

题目大意：两种操作，1是改动区间上l到r上面德值为x，2是询问l到r区间总的改动值。

解题思路：线段树模板题。

#include <cstdio>

#include <cstring>

#include <cstdlib>

#include <algorithm>

using namespace std;

const int maxn = 5*1e5;

typedef long long ll;

ll s[maxn], del[maxn], mark[maxn];

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

    if (l < r) {

        int mid = (l + r)/2;

        build(u*2, l, mid);

        build(u*2+1, mid+1, r);

    } else

        mark[u] = l;

}

ll query (int u, int l, int r, int x, int y) {

    if (y < l || x > r)

        return 0;

    if (x <= l && r <= y)

        return s[u];

    int mid = (l + r) / 2;

    ll L = query(u*2, l, mid, x, y);

    ll R = query(u*2+1, mid+1, r, x, y);

    return L + R + max(0, min(r, y) - max(l, x) + 1) * del[u];

}

void clear (int u, int l, int r, int z) {

    if (mark[u]) {

        del[u] += abs(mark[u]-z);

        s[u] += 1LL * (r-l+1) * abs(mark[u]-z);

        mark[u] = 0;

    } else {

        if (l == r)

            return;

        int mid = (l + r) / 2, lc = u*2, rc = u*2+1;

        clear(lc, l, mid, z);

        clear(rc, mid+1, r, z);

        s[u] = s[lc] + s[rc] + 1LL * (r-l+1) * del[u];

    }

}

void modify (int u, int l, int r, int x, int y, int z) {

    //    printf("%d %d %d %d %d %d\n", u, l, r, x, y, z);

    if (y < l || x > r)

        return;

    if (x <= l && r <= y) {

        clear(u, l, r, z);

        mark[u] = z;

        return;

    }

    int mid = (l + r) / 2, lc = u*2, rc = u*2+1;

    if (mark[u]) {

        mark[lc] = mark[rc] = mark[u];

        mark[u] = 0;

    }

    modify(lc, l, mid, x, y, z);

    modify(rc, mid+1, r, x, y, z);

    s[u] = s[lc] + s[rc] + 1LL * (r-l+1) * del[u];

}

int main () {

    int n, m;

    scanf("%d%d", &n, &m);

    /*

       memset(sum, 0, sizeof(sum));

       memset(del, 0, sizeof(del));

       memset(mark, 0, sizeof(mark));

       */

    build(1, 1, n);

    int type, x, y, z;;

    for (int i = 0; i < m; i++) {

        scanf("%d%d%d", &type, &x, &y);

        if (type == 1) {

            scanf("%d", &z);

            modify(1, 1, n, x, y, z);

        } else

            printf("%lld\n", query(1, 1, n, x, y));

    }

    return 0;

}